Voltage-dependent non-linear resistance ceramic composition

ABSTRACT

It is a voltage-dependent non-linear resistance ceramic composition comprising SrTiO 3  as host material, Dy 2  O 3  or Dy 2  O 3  and Nb 2  O 5  or Ta 2  O 5  or Ta 2  O 5  and Nb 2  O 5  as accelerating agent for semiconductorization, thereby changing crystal to a low resistance, and changing crystal boundary to a high resistance. 
     In case Dy 2  O 3  or Dy 2  O 3  and Nb 2  O 5  are used as the accelerating agent for semiconductorization, one kind or more selected from the group consisting of Na, K, Ca, Cd, In, Ba, Pb, Ag, Ce, La, Sc, Y, Cs, Au, Mg, Zr, Sn, Sb, W, Bi, Ni, Fe, Ga, Pt, Tl, Al, Si, Be, Li, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf and Ru. Alternatively, in case Ta 2  O 5  or Ta 2  O 5  and Nb 2  O 5  are used as the accelerating agent for semiconductorization, one kind or more selected from the group consisting of Na, K, Ca, Cd, In, Ba, Pb, Mg, Zr, Sn, Sb, W, Bi, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf, Ru, Ga, Pt, Tl, La, Sc, Y, Cs, and Au. 
     As a result, baristor characteristic is obtainable by means of the high resistance at crystal boundaries and capacitor between crystal granules--crystal boundary--crystal granule. 
     From this matter, an element having both functions of the baristor characteristics and the capacitor characteristics are obtainable, and performs effect in surge absorption and noise elimination.

This application is a continuation of application Ser. No. 07/021,588, filed Mar. 2, 1987, now abandoned, which was a continuation of application Ser. No. 06/668,383 filed Oct. 9, 1984, abandoned.

TECHNICAL FIELD

The present invention relates to a voltage dependent non-linear resistance ceramic composition for use in surge absorbing and noise elimination in various electric apparatuses and electronic apparatuses.

BACKGROUND ART

Heretofore, in various electric apparatuses and electronic apparatuses, in order to absorb extraordinary high voltage, elimination of noise, elimination of arc, and the like, SiC baristors or varistors of ZnO system having a voltage-dependent non-linear resistance characteristics are used. Voltage-current characteristic of such baristors can be approximately represented by the following equation:

    I=(V/C).sup.α,

wherein I is current, V is voltage, C is a constant proper for the baristor, and α is a voltage non-linearity exponent.

The α of the SiC baristor is about 2-7, and for the ZnO system baristor there is ones that reaching 50. Though such baristors has superior characteristic for absorbing relatively high voltage called surge, for voltages lower than baristor voltage (for instance, absorption of noise) almost no effect is represented since its dielectric constant is low and its inherent capacitance is small, and their dielectric loss angle tan δ are so large as 5-10%.

On the other hand, for elimination of low voltage noise, static electricity, or the like, by appropriately selecting composition and firing condition, semiconductor ceramic capacitors having apparent dielectric constant of about 5×10⁴ -6×10⁴ and tan δ of about 1% are utilized.

However, these semiconductor ceramic capacitor is liable to be destroyed or become to be non-functional as capacitors when extraordinary high voltage such as surge is impressed thereon or a current above a certain limit is impressed on the element. For such reason, in the electric apparatuses or electronic apparatuses, for the purpose of both the absorbing of high voltage surge and the elimination of low voltage noise, the baristors are used being combined with capacitors and other component (for instance, coil), and for instance, a noise filter has such configuration.

FIG. 1 shows general noise filter circuit, FIG. 2 shows conventional noise filter circuit constituted by combining a baristor, capacitors and a coil, and 1 is the coil, 2 are the capacitors and 3 is the baristor.

When a noise input A shown in FIG. 5 is impressed on these circuits, output characteristic from general noise filter circuit of FIG. 1 is such as C of FIG. 5, and noise is not eliminated sufficiently. Output characteristic from the conventional noise filter circuit including a baristor shown in FIG. 2 is such as B of FIG. 5, and though noise is eliminated, such configuration has a shortcoming that it has large number of components in the inside of the apparatus and besides is contrary to tendency of miniaturization of the apparatus.

Accordingly, an electronic component, which absorbs extraordinary high voltage, can eliminate low voltage, such as noise and has small number of components, and capable of miniaturization, is demanded.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention intends to provide a voltage-dependent non-linear resistance ceramic composition comprising 80.000-99.990 mol % of SrTiO₃ and as metal oxide for semiconductorization acceleration 0.005-10.000 mol % of Dy₂ O₃ or the above-mentioned amount of Dy₂ O₃ and 0.001-0.200 mol % of Nb₂ O₅, and is characterized by containing 0.005-10.000 mol % in the form of oxide of at least one kind of element selected from the group consisting of K, Ca, Cd, In, Ba, Cs, Zr, Sn, W, Ni, Fe, Pt, Tl, Si, Be, Li, Ir, Os, Hf and Ru, which segregates at grain boundary to make the grain boundary to high resistance.

Furthermore, the present invention intends to provide a voltage-dependent non-linear resistance ceramic composition comprising 80.000-99.990 mol % of SrTiO₃ and as metal oxide for semiconductorization acceleration 0.005-10.000 mol % of Ta₂ O₅ or the above-mentioned amount of Ta₂ O₅ and 0.001-0.200 mol % of Nb₂ O₅, and is characterized by containing 0.005-10.000 mol % in the form of oxide of at least one kind of element selected from the group consisting of Ca, Cd, In, Ba, Sn, Sb, W, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf, Ru, Pt, Tl, La, Y, Cs and which segregates at grain boundry to make the grain boundary to a high resistance.

The present invention can also provide a voltage-dependent non-linear resistance ceramic composition comprising 79.800-99.989 mol % of SrTiO₃ and as metal oxide for semiconductorization acceleration 0.005-10.000 mol % of Dy₂ O₃, 0.001-0.200 mol % of Nb₂ O₅, and is characterized by containing 0.005-10.00 mol % in the form of oxide(s) of one or more element selected from the group consisting of Ca, Cd, In, Ba, Cs, Zr, Sn, W, Ni, Fe, Pt, Tl, Si, Be, Li, Ir, Os, Hf, and Ru, which segregates at grain boundary to make the grain boundary to high resistance.

The present invention can also provide a voltage-dependent non-linear resistance ceramic composition comprising 78.000-99.989 mol % of SrTiO₃ and as metal oxide for semiconductorization acceleration 0.005-10.000 mol % of Ta₂ O₅, 0.001-0.200 mol % of Nb₂ O₅, and is characterized by containing 0.005-10.000 mol % in the form of oxide(s) of one or more element selected from the group consisting of Ca, Cd, In, Ba, Sn, Sb, W, La, Y, Cs, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf and Ru, which segregates at grain boundary to make the grain boundary to high resistance.

BRIEF EXPLANATION OF THE DRAWING

FIG. 1 is a circuit diagram of a general noise filter, FIG. 2 is a circuit diagram of a noise filter using the conventional baristors and the capacitors, FIG. 3 is a sectional view of an element using voltage dependent non-linear resistance ceramic composition in accordance with the present invention, FIG. 4 is a circuit diagram of a noise filter using the voltage dependent non-linear resistance ceramic composition in accordance with the present invention, FIG. 5 is a characteristic chart showing situation of input noise and output in accordance with circuit of noise filters of the present invention and the prior art.

THE BEST MODE FOR EMBODYING THE INVENTION

As a result of accumulating various experiments the inventors propose a voltage dependent non-linear resistance ceramic composition in a different system from the conventional composition by making strontium-titanate (SrTiO₃) as host material, and adding either one of Dy₂ O₃ or Ta₂ O₅ as semiconductorization accelerating agent, and by further adding depending on necessity appropriate amount of additives; hereafter the present invention is described with respect to embodiments.

EXAMPLE 1

After measuring SrTiO₃ and Dy₂ O₃ and BaO to become composition ratio as shown in the below-mentioned Table 1, they are blended for 6 hours in wet method in a ball-mill or the like, and after drying is calcinated for 1-5 hours at 1000°-1250° C. in the air. Thereafter, after grinding for 4 hours in wet method in ball mill or the like and subsequently drying, and after granulating by adding 8 wt % of organic binder (for instance, polovinylalcohol), press-forming to the size of 8.0 (mm)φ×1.0 (mm) t with a pressing force of 1.0 t/cm². The granulated body is fired in a reducing admosphere (for instance, N₂ :H₂ =10:1) at 1300°-1450° C. for 1-6 hours. The fired body thus obtained has a specific resistance of 0.1-0.8 Ω.cm, and average granular size is 20-50μm. Then, the fired body is further fired in air at 1000°-1300° C. for 0.5-5 hours, to obtain fired body 4 of FIG. 3. Furthermore, the both faces of the fired body 4 are ground with abrasive such as SiC. Diameter of the above-mentioned electrodes 5, 6 are selected to be 5.0 (mm) φ.

Characteristics of the element thus obtained are shown in TABLE 1.

                                      TABLE 1                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Dy.sub.2 O.sub.3                                                                    BaO V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              98      1.0                                                                               4.0 × 10.sup.3                                                                41.6                                          2*  99.800                                                                             0    0.200                                                                              86      1.7                                                                               4.0 × 10.sup.3                                                                33.7                                          3*  99.000                                                                             0    1.000                                                                              82      2.0                                                                               5.0 × 10.sup.3                                                                31.9                                          4*  90.000                                                                             0    10.000                                                                             65      2.9                                                                               8.0 × 10.sup.3                                                                24.7                                          5*  99.995                                                                             0.005                                                                               0   39      3.2                                                                               6.0 × 10.sup.3                                                                9.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              68      6.4                                                                               1.0 × 10.sup.4                                                                5.4                                           7   99.795                                                                             0.005                                                                               0.200                                                                              59      9.1                                                                               1.8 × 10.sup.4                                                                3.3                                           8   98.995                                                                             0.005                                                                               1.000                                                                              43      17.7                                                                              2.0 × 10.sup.4                                                                2.7                                           9   89.995                                                                             0.005                                                                               10.000                                                                             30      18.0                                                                              2.5 × 10.sup.4                                                                3.5                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             26      11.5                                                                              2.6 × 10.sup.4                                                                8.8                                           11* 99.800                                                                             0.200                                                                               0   16      5.1                                                                               8.0 × 10.sup.3                                                                6.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              53      17.7                                                                              1.7 × 10.sup.4                                                                3.4                                           13  99.600                                                                             0.200                                                                               0.200                                                                              45      18.7                                                                              2.4 × 10.sup.4                                                                2.3                                           14  98.800                                                                             0.200                                                                               1.000                                                                              31      21.3                                                                              2.9 × 10.sup.4                                                                2.5                                           15  89.800                                                                             0.200                                                                               10.000                                                                             23      23.4                                                                              3.6 × 10.sup.4                                                                3.2                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             22      20.5                                                                              3.7 × 10.sup.4                                                                11.1                                          17* 99.000                                                                             0.200                                                                               0   13      6.0                                                                               9.0 × 10.sup.3                                                                8.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              40      13.2                                                                              1.4 × 10.sup.4                                                                2.8                                           19  98.800                                                                             1.000                                                                               0.200                                                                              32      18.2                                                                              2.6 × 10.sup.4                                                                2.3                                           20  98.000                                                                             1.000                                                                               1.000                                                                              19      21.8                                                                              3.1 × 10.sup.4                                                                2.1                                           21  89.000                                                                             1.000                                                                               10.000                                                                             15      20.2                                                                              3.8 × 10.sup.4                                                                3.1                                           22* 84.000                                                                             1.000                                                                               15.000                                                                             16      20.1                                                                              4.2 × 10.sup.4                                                                9.4                                           23* 90.000                                                                             10.000                                                                              0   21      6.4                                                                               5.0 × 10.sup.3                                                                9.4                                           24  89.995                                                                             10.000                                                                              0.005                                                                              34      15.4                                                                              1.8 × 10.sup.4                                                                3.1                                           25  89.800                                                                             10.000                                                                              0.200                                                                              29      22.0                                                                              2.2 × 10.sup.4                                                                2.2                                           26  89.000                                                                             10.000                                                                              1.000                                                                              18      23.8                                                                              2.6 × 10.sup.4                                                                2.4                                           27  80.000                                                                             10.000                                                                              10.000                                                                             10      17.7                                                                              1.9 × 10.sup.4                                                                3.5                                           28* 75.000                                                                             10.000                                                                              15.000                                                                             14      13.2                                                                              1.7 × 10.sup.4                                                                6.9                                           29* 85.000                                                                             15.000                                                                              0   38      5.3                                                                               7.0 × 10.sup.3                                                                10.7                                          30* 84.995                                                                             15.000                                                                              0.005                                                                              23      8.6                                                                               8.0 × 10.sup.3                                                                8.7                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              17      11.8                                                                              9.0 × 10.sup.3                                                                9.7                                           32* 84.000                                                                             15.000                                                                              1.000                                                                              19      9.8                                                                               1.0 × 10.sup.4                                                                9.9                                           33* 75.000                                                                             15.000                                                                              10.000                                                                             24      8.7                                                                               8.0 × 10.sup.3                                                                15.8                                          34* 70.000                                                                             15.000                                                                              15.000                                                                             39      4.2                                                                               4.0 × 10.sup.3                                                                18.1                                          __________________________________________________________________________

Herein, evaluation of characteristics of the elements as baristor can be made by α and C in a voltage-current characteristic equation:

    I=(V/C).sup.α

(wherein I is current, V is voltage, C is a constant proper to the baristor and α is a non-linearity exponent). Since accurate measurement of C is difficult, in the present invention, characteristic assesment as baristor is made by the value of baristor voltage for unit thickness when 1 mA of baristor current is flowed (hereinafter is called as V₁ mA/mm.) and by a value of

    α=1/log (V.sub.10 mA/V.sub.1 mA)

(wherein V₁₀ mA is a baristor voltage when a baristor current of 10 mA is flowed and V₁ mA is a baristor voltage when baristor current of 1 mA is flowed).

And characteristic assessment as the capacitors are made by a dielectric constant and dielectric loss tan δ at a measurement frequency of 1 KHz. The above-mentioned data are those for firing temperature and time in the reducing atmosphere was 1400° C. and 2 hours, respectively and firing temperature and time in air was 1200° C. and 3 hours, respectively.

EXAMPLE 2

SrTiO₃, Dy₂ O₄ and ZrO₂ are in a composition ratio shown in the below-mentioned TABLE 2, and mixing, forming and firings are carried in a similar operation as the above-mentioned EXAMPLE 1, and measurements are made in the similar conditions and results are shown in TABLE 2.

                                      TABLE 2                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Dy.sub.2 O.sub.3                                                                    ZrO.sub.2                                                                          V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              101     1.0                                                                               4.0 × 10.sup.3                                                                9.2                                           2*  99.800                                                                             0    0.200                                                                              127     1.9                                                                               4.0 × 10.sup.3                                                                4.4                                           3*  99.000                                                                             0    1.000                                                                              171     2.3                                                                               7.0 × 10.sup.3                                                                1.3                                           4*  90.000                                                                             0    10.000                                                                             196     2.8                                                                               8.0 × 10.sup.3                                                                4.5                                           5*  99.995                                                                             0.005                                                                               0   39      3.2                                                                               6.0 × 10.sup.3                                                                9.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              64      6.7                                                                               1.1 × 10.sup.4                                                                5.4                                           7   99.795                                                                             0.005                                                                               0.200                                                                              71      10.3                                                                              1.7 × 10.sup.4                                                                2.9                                           8   98.995                                                                             0.005                                                                               1.000                                                                              78      19.8                                                                              2.2 × 10.sup.4                                                                2.4                                           9   89.995                                                                             0.005                                                                               10.000                                                                             86      21.0                                                                              2.7 × 10.sup.4                                                                2.6                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             95      17.8                                                                              2.7 × 10.sup.4                                                                7.4                                           11* 99.800                                                                             0.200                                                                               0   16      5.1                                                                               8.0 × 10.sup.3                                                                6.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              56      14.2                                                                              1.9 × 10.sup.4                                                                3.2                                           13  99.600                                                                             0.200                                                                               0.200                                                                              51      19.9                                                                              3.1 × 10.sup.4                                                                2.8                                           14  98.800                                                                             0.200                                                                               1.000                                                                              49      22.0                                                                              3.5 × 10.sup.4                                                                2.3                                           15  89.800                                                                             0.200                                                                               10.000                                                                             58      20.7                                                                              3.8 × 10.sup.4                                                                2.9                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             81      19.7                                                                              3.2 × 10.sup.4                                                                9.2                                           17* 99.000                                                                             1.000                                                                               0   13      6.0                                                                               9.0 × 10.sup.3                                                                8.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              59      12.4                                                                              2.0 × 10.sup.4                                                                3.7                                           19  98.800                                                                             1.000                                                                               0.200                                                                              65      19.9                                                                              3.1 × 10.sup.4                                                                3.1                                           20  98.000                                                                             1.000                                                                               1.000                                                                              77      20.9                                                                              3.8 × 10.sup.4                                                                3.2                                           21  89.000                                                                             1.000                                                                               10.000                                                                             83      22.0                                                                              4.4 × 10.sup.4                                                                3.9                                           22* 84.000                                                                             1.000                                                                               15.000                                                                             107     14.6                                                                              4.3 × 10.sup.4                                                                9.8                                           23* 90.000                                                                             10.000                                                                              0   21      6.4                                                                               5.0 × 10.sup.3                                                                9.4                                           24  89.800                                                                             10.000                                                                              0.005                                                                              90      16.9                                                                              1.8 × 10.sup.4                                                                4.0                                           25  89.800                                                                             10.000                                                                              0.200                                                                              95      19.4                                                                              2.6 × 10.sup.4                                                                3.3                                           26  89.000                                                                             10.000                                                                              1.000                                                                              98      21.9                                                                              3.1 × 10.sup.4                                                                3.0                                           27  80.000                                                                             10.000                                                                              10.000                                                                             140     23.3                                                                              2.9 × 10.sup.4                                                                4.7                                           28* 75.000                                                                             10.000                                                                              15.000                                                                             171     21.0                                                                              2.7 × 10.sup.4                                                                6.9                                           29* 85.000                                                                             15.000                                                                              0   38      5.3                                                                               7.0 × 10.sup.3                                                                10.7                                          30* 84.995                                                                             15.000                                                                              0.005                                                                              92      9.4                                                                               8.0 × 10.sup.3                                                                8.0                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              96      11.2                                                                              1.0 × 10.sup.4                                                                8.0                                           32* 84.000                                                                             15.000                                                                              1.000                                                                              117     10.8                                                                              1.1 × 10.sup.4                                                                9.7                                           33* 75.000                                                                             15.000                                                                              10.000                                                                             169     9.5                                                                               7.0 × 10.sup.3                                                                12.4                                          34* 70.000                                                                             15.000                                                                              15.000                                                                             192     9.0                                                                               4.0 × 10.sup.3                                                                23.3                                          __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 3

SrTiO₃, Dy₂ O₃ and NiO are in a composition ratio shown in the below-mentioned TABLE 3, and mixing, forming and firings are carried in a similar operation as the above-mentioned EXAMPLE 1, and measurements are made in the similar conditions and results are shown in TABLE 3.

                                      TABLE 3                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Dy.sub.2 O.sub.3                                                                    NiO V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              98      1.0                                                                               4.0 × 10.sup.3                                                                40.4                                          2*  99.800                                                                             0    0.200                                                                              90      1.8                                                                               4.0 × 10.sup.3                                                                33.9                                          3*  99.000                                                                             0    1.000                                                                              87      2.1                                                                               5.0 × 10.sup.3                                                                30.0                                          4*  90.000                                                                             0    10.000                                                                             62      2.9                                                                               9.0 × 10.sup.3                                                                26.0                                          5*  99.995                                                                             0.005                                                                               0   39      3.2                                                                               6.0 × 10.sup.3                                                                9.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              78      6.1                                                                               1.0 × 10.sup.4                                                                6.4                                           7   99.795                                                                             0.005                                                                               0.200                                                                              60      9.4                                                                               1.6 × 10.sup.4                                                                3.2                                           8   98.995                                                                             0.005                                                                               1.000                                                                              44      16.8                                                                              1.9 × 10.sup.4                                                                2.6                                           9   89.995                                                                             0.005                                                                               10.000                                                                             29      18.3                                                                              2.2 × 10.sup.4                                                                3.9                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             25      10.7                                                                              2.6 × 10.sup.4                                                                8.0                                           11* 99.800                                                                             0.200                                                                               0   16      5.1                                                                               8.0 × 10.sup.3                                                                6.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              63      14.7                                                                              2.1 × 10.sup.4                                                                3.8                                           13  99.660                                                                             0.200                                                                               0.200                                                                              50      17.1                                                                              2.9 × 10.sup.4                                                                2.8                                           14  98.880                                                                             0.200                                                                               1.000                                                                              36      20.3                                                                              3.2 × 10.sup.4                                                                2.6                                           15  89.880                                                                             0.200                                                                               10.000                                                                             26      19.4                                                                              3.5 × 10.sup.4                                                                3.4                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             23      18.1                                                                              3.8 × 10.sup.4                                                                8.8                                           17* 99.000                                                                             1.000                                                                               0   13      6.0                                                                               9.0 × 10.sup.3                                                                8.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              51      14.0                                                                              2.5 × 10.sup.4                                                                3.0                                           19  98.800                                                                             1.000                                                                               0.200                                                                              32      19.1                                                                              3.2 × 10.sup.4                                                                2.7                                           20  98.000                                                                             1.000                                                                               1.000                                                                              21      22.7                                                                              3.7 × 10.sup.4                                                                2.4                                           21  89.000                                                                             1.000                                                                               10.000                                                                             17      23.6                                                                              38 × 10.sup.4                                                                 2.8                                           22* 84.000                                                                             1.000                                                                               15.000                                                                             16      23.2                                                                              4.4 × 10.sup.4                                                                10.1                                          23* 90.000                                                                             10.000                                                                              0   21      6.4                                                                               5.0 × 10.sup.3                                                                9.4                                           24  89.995                                                                             10.000                                                                              0.005                                                                              44      15.4                                                                              1.8 × 10.sup.4                                                                3.1                                           25  89.800                                                                             10.000                                                                              0.200                                                                              31      20.9                                                                              2.2 × 10.sup.4                                                                2.4                                           26  89.000                                                                             10.000                                                                              1.000                                                                              19      22.0                                                                              2.4 × 10.sup.4                                                                3.0                                           27  80.000                                                                             10.000                                                                              10.000                                                                             12      13.9                                                                              1.9 × 10.sup.4                                                                4.6                                           28* 75.000                                                                             10.000                                                                              15.000                                                                             14      9.8                                                                               1.5 × 10.sup.4                                                                6.3                                           29* 85.000                                                                             15.000                                                                              0   38      5.3                                                                               7.0 × 10.sup.3                                                                10.7                                          30* 84.995                                                                             15.000                                                                              0.005                                                                              22      9.9                                                                               7.0 × 10.sup.3                                                                8.1                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              17      12.3                                                                              9.0 × 10.sup.3                                                                7.9                                           32* 84.000                                                                             15.000                                                                              1.000                                                                              14      9.9                                                                               8.0 × 10.sup.3                                                                9.2                                           33* 75.000                                                                             15.000                                                                              10.000                                                                             19      8.7                                                                               7.0 × 10.sup.3                                                                9.8                                           34* 70.000                                                                             15.000                                                                              15.000                                                                             35      6.3                                                                               5.0 × 10.sup.3                                                                22.1                                          __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 4

SrTiO₃, Dy₂ O₃ and SiO₂ are in a composition ratio shown in the below-mentioned TABLE 4, and mixing, forming and firings are carried in a similar operation as the above-mentioned EXAMPLE 1, and measurements are made in the similar conditions and results are shown in TABLE 4.

                                      TABLE 4                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Dy.sub.2 O.sub.3                                                                    SiO.sub.2                                                                          V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              90      1.0                                                                               3.0 × 10.sup.3                                                                35.0                                          2*  99.800                                                                             0    0.200                                                                              106     1.5                                                                               2.0 × 10.sup.3                                                                38.1                                          3*  99.000                                                                             0    1.000                                                                              114     2.6                                                                               3.0 × 10.sup.3                                                                41.4                                          4*  90.000                                                                             0    10.000                                                                             198     2.7                                                                               4.0 × 10.sup.3                                                                59.3                                          5*  99.995                                                                             0.005                                                                               0   39      3.2                                                                               6.0 × 10.sup.3                                                                9.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              40      8.1                                                                               1.3 × 10.sup.4                                                                4.2                                           7   99.795                                                                             0.005                                                                               0.200                                                                              37      10.2                                                                              1.7 × 10.sup.4                                                                3.8                                           8   98.995                                                                             0.005                                                                               1.000                                                                              35      12.5                                                                              1.5 × 10.sup.4                                                                2.9                                           9   89.995                                                                             0.005                                                                               10.000                                                                             43      14.9                                                                              1.4 × 10.sup.4                                                                3.0                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             60      15.2                                                                              9.0 × 10.sup.3                                                                8.1                                           11* 99.800                                                                             0.200                                                                               0   16      5.1                                                                               8.0 × 10.sup.3                                                                6.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              17      10.5                                                                              1.6 × 10.sup.4                                                                3.9                                           13  99.600                                                                             0.200                                                                               0.200                                                                              15      14.2                                                                              3.0 × 10.sup.4                                                                3.0                                           14  98.800                                                                             0.200                                                                               1.000                                                                              24      18.7                                                                              4.5 × 10.sup.4                                                                2.9                                           15  89.800                                                                             0.200                                                                               10.000                                                                             30      19.2                                                                              4.4 × 10.sup.4                                                                3.3                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             58      16.2                                                                              2.5 × 10.sup.4                                                                7.9                                           17* 99.000                                                                             1.000                                                                               0   13      6.0                                                                               9.0 × 10.sup.3                                                                8.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              15      10.0                                                                              1.8 × 10.sup.4                                                                3.1                                           19  98.800                                                                             1.000                                                                               0.200                                                                              25      12.6                                                                              3.0 × 10.sup.4                                                                3.3                                           20  98.000                                                                             1.000                                                                               1.000                                                                              34      15.7                                                                              2.3 × 10.sup.4                                                                3.7                                           21  89.000                                                                             1.000                                                                               10.000                                                                             55      16.4                                                                              1.9 × 10.sup.4                                                                4.8                                           22* 84.000                                                                             1.000                                                                               15.000                                                                             90      14.4                                                                              1.0 × 10.sup.4                                                                7.5                                           23* 90.000                                                                             10.000                                                                              0   64      6.4                                                                               5.0 × 10.sup.3                                                                9.4                                           24  89.995                                                                             10.000                                                                              0.005                                                                              109     10.9                                                                              1.2 × 10.sup.4                                                                2.6                                           25  89.800                                                                             10.000                                                                              0.200                                                                              156     15.6                                                                              1.9 × 10.sup.4                                                                2.9                                           26  89.000                                                                             10.000                                                                              1.000                                                                              162     16.2                                                                              1.4 × 10.sup.4                                                                3.1                                           27  80.000                                                                             10.000                                                                              10.000                                                                             178     17.8                                                                              1.3 × 10.sup.4                                                                3.5                                           28* 75.000                                                                             10.000                                                                              15.000                                                                             190     19.0                                                                              9.0 × 10.sup.3                                                                6.5                                           29* 85.000                                                                             15.000                                                                              0   53      5.3                                                                               7.0 × 10.sup.3                                                                10.7                                          30* 84.995                                                                             15.000                                                                              0.005                                                                              75      7.5                                                                               1.7 × 10.sup.4                                                                9.8                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              76      7.6                                                                               1.5 × 10.sup.4                                                                10.2                                          32* 84.000                                                                             15.000                                                                              1.000                                                                              81      8.1                                                                               1.1 × 10.sup.4                                                                18.4                                          33* 75.000                                                                             15.000                                                                              10.000                                                                             93      9.3                                                                               7.0 × 10.sup.3                                                                24.4                                          34* 70.000                                                                             15.000                                                                              15.000                                                                             65      6.5                                                                               4.0 × 10.sup.3                                                                29.3                                          __________________________________________________________________________      *Comparison sample                                                       

As shown by EXAMPLEs 1 through 4, Dy₂ O₃ with its added value in a range of 0.005-10.000 mol %, contributes to reduce specific resistance of the reduced fired body, and by re-firing in air it shows baristor characteristics.

This is because that granules and grain boundaries of fied body obtained by the reduced firing is of low resistances, and by re-firing in the air only crystal boundaries become to high resistance thereby forming electric barriers.

However, when only Dy₂ O₃ is added, the electric barrier formed at the grain boundaries are small, and the baristor characteristics are relatively small.

Accordingly, by adding additives such as BaO, ZrO₂, NiO, SiO₂, Gd₂ O₃, the additive is segregated at the grain boundaries during the reduced firing, and by re-firing in the air such additive forms large electric barrier at the grain boundary, thereby making the baristor characteristics large.

And, by making the crystal grain boundary only in high resistance, capacitance characteristics is presented between crystal granule--crystal grain boundaries--crystal granules.

Accordingly, by adding Dy₂ O₃ and additive such as BaO, CeO₂, La₂ O₃, Y₂ O₃, ZrO₂, NiO, Ga₂ O₃, SiO₂, to SrTiO₃, it is possible to provide characteristics combining the baristor characteristics and the capacitance characteristics.

The case such effect is presented is within a range that Py₂ O₃ is 0.005-10.000 mol %, BaO, ZrO₂, NiO, SiO₂ or is 0.005-10.000 mol %.

Though in the above-mentioned EXAMPLEs 1-9, the elucidation was made for the cases where an additive was added in a single one, it was confirmed that when in place of the above-mentioned, an oxide of Ca, Cd, In, Cs, Sn, W, Fe, Pt, Tl, Be, Li, Lu, Th, Ir, Os, Hf, Ru as single one in a range of the above-mentioned predetermined amount was added, the similar effect was obtained.

Besides, it was confirmed that the same effect was obtained even when two kinds or more of oxides of these Ca, Cd, In, Ba, Pb, Cs, Zr, Sn, W, Ni, Fe, Pt, Tl, Si, Be, Li, Ir, Os, Hf and Ru were used in a manner that total added amount is within the above-mentioned range.

EXAMPLE 5

After measuring SrTiO₃, extremely small amount of Nb₂ O₅ which was existing from the initial stage of material (Nb₂ O₅ content in the material used in the present example was 0.050 mol %), Dy₂ O₃ as oxide of metal for acceleration of semiconductorization and CaO as element to improve non-linearity to become composition ratios shown in the below-mentioned TABLE 10, they were mixed and ground and dried, and thereafter calcinated at 1000° C. for 4 hours. Thereafter, it was ground in wet method by ball mill or the like for 4 hours, and dried, and subsequently, after granulating adding 8 wt % of an organic binder (for instance, polyvinylalcohol), press-formed into a shape of disc of 8.0φ (mm)×1.0 t (mm) with forming pressure of about 1.0 t/cm². The formed body was fired for 4 hours in a reducing atmosphere (for instance, N₂ :H₂ =1:1, flow rate is 1.0 l/min) and at 1350° C. Specific resistance of the fired body thus obtained was averagely 0.3 Ω.cm, and average granule size was 30 μm.

Nextly, the above-mentioned fired body was baked in the air for 2 hours at 1300° C. to obtain a sintered body 4 of FIG. 3. And both faces of the above-mentioned sintered body 4 are ground by using an abrasive such as SiC or the like, and electrodes 5, 6 are formed by using conductive metal such as Ag on the ground faces. Sizes of the electrodes 5, 6 are circle of 5.0φ (mm).

Characteristics of the devices thus obtained are shown in TABLE 5.

                                      TABLE 5                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                      Characteristics                                            No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Dy.sub.2 O.sub.3                                                                   Cao V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                           tan δ (%)                            __________________________________________________________________________     1*  99.945                                                                             0.050                                                                              0   0.005                                                                              100     1.0                                                                               4.0 × 10.sup.3                                                                41.6                                       2*  99.750                                                                             0.050                                                                              0   0.200                                                                              88      1.2                                                                               4.0 × 10.sup.3                                                                33.7                                       3*  98.950                                                                             0.050                                                                              0   1.000                                                                              84      1.4                                                                               5.0 × 10.sup.3                                                                31.9                                       4*  89.950                                                                             0.050                                                                              0   10.000                                                                             75      1.7                                                                               9.0 × 10.sup.3                                                                27.4                                       5*  99.945                                                                             0.050                                                                              0.005                                                                              0   41      3.2                                                                               6.0 × 10.sup.3                                                                9.8                                        6   99.940                                                                             0.050                                                                              0.005                                                                              0.005                                                                              70      6.4                                                                               1.0 × 10.sup.4                                                                5.3                                        7   99.745                                                                             0.050                                                                              0.005                                                                              0.200                                                                              61      9.0                                                                               1.8 × 10.sup.4                                                                3.3                                        8   98.945                                                                             0.050                                                                              0.005                                                                              1.000                                                                              48      11.7                                                                              2.1 × 10.sup.4                                                                2.7                                        9   89.945                                                                             0.050                                                                              0.005                                                                              10.000                                                                             43      12.0                                                                              2.3 × 10.sup.4                                                                3.9                                        10* 84.945                                                                             0.050                                                                              0.005                                                                              15.000                                                                             40      11.5                                                                              2.5 × 10.sup.4                                                                8.4                                        11* 99.750                                                                             0.050                                                                              0.200                                                                              0   36      5.1                                                                               7.0 × 10.sup.3                                                                6.7                                        12  99.745                                                                             0.050                                                                              0.200                                                                              0.005                                                                              68      7.7                                                                               1.1 × 10.sup.4                                                                2.4                                        13  99.550                                                                             0.050                                                                              0.200                                                                              0.200                                                                              65      10.2                                                                              1.7 × 10.sup.4                                                                2.3                                        14  98.750                                                                             0.050                                                                              0.200                                                                              1.000                                                                              61      11.3                                                                              2.4 × 10.sup.4                                                                2.5                                        15  89.750                                                                             0.050                                                                              0.200                                                                              10.000                                                                             61      12.4                                                                              2.9 × 10.sup.4                                                                2.6                                        16* 84.750                                                                             0.050                                                                              0.200                                                                              15.000                                                                             60      11.5                                                                              2.6 × 10.sup.4                                                                8.7                                        17* 98.950                                                                             0.050                                                                              1.000                                                                              0   33      6.0                                                                               8.0 × 10.sup.3                                                                8.0                                        18  98.945                                                                             0.050                                                                              1.000                                                                              0.005                                                                              65      8.2                                                                               1.0 × 10.sup.4                                                                2.8                                        19  98.750                                                                             0.050                                                                              1.000                                                                              0.200                                                                              57      10.8                                                                              1.6 × 10.sup.4                                                                2.4                                        20  97.950                                                                             0.050                                                                              1.000                                                                              1.000                                                                              49      11.2                                                                              2.1 × 10.sup.4                                                                2.6                                        21  88.950                                                                             0.050                                                                              1.000                                                                              10.000                                                                             45      12.1                                                                              2.8 × 10.sup.4                                                                3.3                                        22* 83.950                                                                             0.050                                                                              1.000                                                                              15.000                                                                             54      11.6                                                                              2.4 × 10.sup.4                                                                10.4                                       23* 89.950                                                                             0.050                                                                              10.000                                                                             0   42      6.4                                                                               5.0 × 10.sup.3                                                                9.4                                        24  89.945                                                                             0.050                                                                              10.000                                                                             0.005                                                                              64      8.5                                                                               1.0 × 10.sup.4                                                                3.0                                        25  89.750                                                                             0.050                                                                              10.000                                                                             0.200                                                                              59      9.9                                                                               1.7 × 10.sup.4                                                                2.4                                        26  88.950                                                                             0.050                                                                              10.000                                                                             1.000                                                                              48      11.0                                                                              2.0 × 10.sup.4                                                                2.7                                        27  79.950                                                                             0.050                                                                              10.000                                                                             10.000                                                                             60      12.4                                                                              2.9 × 10.sup.4                                                                3.9                                        28* 74.950                                                                             0.050                                                                              10.000                                                                             15.000                                                                             64      10.2                                                                              2.7 × 10.sup.4                                                                10.7                                       29* 84.950                                                                             0.050                                                                              15.000                                                                             0   85      5.0                                                                               7.0 × 10.sup.3                                                                10.5                                       30* 84.945                                                                             0.050                                                                              15.000                                                                             0.005                                                                              83      8.6                                                                               8.0 × 10.sup.3                                                                8.2                                        31* 83.750                                                                             0.050                                                                              15.000                                                                             0.200                                                                              77      10.8                                                                              9.0 × 10.sup.3                                                                9.9                                        32* 83.950                                                                             0.050                                                                              15.000                                                                             1.000                                                                              79      9.8                                                                               9.0 × 10.sup.3                                                                10.3                                       33* 74.950                                                                             0.050                                                                              15.000                                                                             10.000                                                                             94      8.1                                                                               8.0 × 10.sup.3                                                                15.9                                       34* 69.950                                                                             0.050                                                                              15.000                                                                             15.000                                                                             128     5.4                                                                               5.0 × 10.sup.3                                                                19.1                                       __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 6

SrTiO₃, very small amount of Nb₂ O₅ which was existing from initial stage of material (contents of Nb₂ O₅ of the material used in the present example was 0.050 mol %), Dy₂ O₃ as oxide of metal for accelerating semicondoctorization and ZrO₂ as an element to improve non-linearity are formed, reduced and fired, and oxidated in the similar operation as that of the above-mentioned EXAMPLE 5. Results obtained by measuring in the similar condition as that of the above-mentioned of the characteristics of devices thus obtained were shown in TABLE 6.

                                      TABLE 6                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                      Characteristics                                            No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Dy.sub.2 O.sub.3                                                                   ZrO.sub.2                                                                          V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                           tan δ (%)                            __________________________________________________________________________     1*  99.945                                                                             0.050                                                                              0   0.005                                                                              103     1.0                                                                               4.0 × 10.sup.3                                                                39.2                                       2*  99.750                                                                             0.050                                                                              0   0.200                                                                              129     1.3                                                                               4.0 × 10.sup.3                                                                34.4                                       3*  98.950                                                                             0.050                                                                              0   1.000                                                                              173     1.9                                                                               7.0 × 10.sup.3                                                                31.5                                       4*  89.950                                                                             0.050                                                                              0   10.000                                                                             198     2.0                                                                               8.0 × 10.sup.3                                                                24.7                                       5*  99.945                                                                             0.050                                                                              0.005                                                                              0   41      3.2                                                                               6.0 × 10.sup.3                                                                9.8                                        6   99.940                                                                             0.050                                                                              0.005                                                                              0.005                                                                              66      6.7                                                                               9.0 × 10.sup.3                                                                5.4                                        7   99.745                                                                             0.050                                                                              0.005                                                                              0.200                                                                              73      9.3                                                                               1.1 × 10.sup.4                                                                2.9                                        8   98.945                                                                             0.050                                                                              0.005                                                                              1.000                                                                              80      10.3                                                                              1.5 × 10.sup.4                                                                2.7                                        9   89.945                                                                             0.050                                                                              0.005                                                                              10.000                                                                             88      11.0                                                                              1.7 × 10.sup.4                                                                2.8                                        10* 84.945                                                                             0.050                                                                              0.005                                                                              15.000                                                                             97      11.4                                                                              1.8 × 10.sup.4                                                                7.4                                        11* 99.750                                                                             0.050                                                                              0.200                                                                              0   36      5.1                                                                               7.0 × 10.sup.3                                                                6.7                                        12  99.745                                                                             0.050                                                                              0.200                                                                              0.005                                                                              76      8.2                                                                               1.3 × 10.sup.4                                                                3.2                                        13  99.550                                                                             0.050                                                                              0.200                                                                              0.200                                                                              71      9.9                                                                               1.7 × 10.sup.4                                                                2.8                                        14  98.750                                                                             0.050                                                                              0.200                                                                              1.000                                                                              69      10.0                                                                              1.9 × 10.sup.4                                                                2.5                                        15  89.750                                                                             0.050                                                                              0.200                                                                              10.000                                                                             78      10.7                                                                              2.5 × 10.sup.4                                                                2.9                                        16* 84.750                                                                             0.050                                                                              0.200                                                                              15.000                                                                             101     11.2                                                                              2.1 × 10.sup.4                                                                9.2                                        17* 98.950                                                                             0.050                                                                              1.000                                                                              0   33      6.0                                                                               8.0 × 10.sup.3                                                                8.0                                        18  98.945                                                                             0.050                                                                              1.000                                                                              0.005                                                                              79      9.9                                                                               1.5 × 10.sup.4                                                                2.7                                        19  98.750                                                                             0.050                                                                              1.000                                                                              0.200                                                                              85      10.4                                                                              1.9 × 10.sup.4                                                                2.5                                        20  97.950                                                                             0.050                                                                              1.000                                                                              1.000                                                                              97      11.0                                                                              2.1 × 10.sup.4                                                                2.4                                        21  88.950                                                                             0.050                                                                              1.000                                                                              10.000                                                                             103     12.0                                                                              2.8 × 10.sup.4                                                                3.0                                        22* 83.950                                                                             0.050                                                                              1.000                                                                              15.000                                                                             127     11.6                                                                              2.3 × 10.sup.4                                                                10.0                                       23* 89.950                                                                             0.050                                                                              10.000                                                                             0   42      6.4                                                                               5.0 × 10.sup.3                                                                9.4                                        24  89.945                                                                             0.050                                                                              10.000                                                                             0.005                                                                              110     10.4                                                                              1.8 × 10.sup.4                                                                3.2                                        25  89.750                                                                             0.050                                                                              10.000                                                                             0.200                                                                              115     10.9                                                                              2.0 × 10.sup.4                                                                2.8                                        26  88.950                                                                             0.050                                                                              10.000                                                                             1.000                                                                              119     11.8                                                                              2.1 × 10.sup.4                                                                3.5                                        27  79.950                                                                             0.050                                                                              10.000                                                                             10.000                                                                             160     12.3                                                                              2.6 × 10.sup.4                                                                4.7                                        28* 74.950                                                                             0.050                                                                              10.000                                                                             15.000                                                                             191     11.0                                                                              2.0 × 10.sup.4                                                                11.9                                       29* 84.950                                                                             0.050                                                                              15.000                                                                             0   85      5.0                                                                               7.0 × 10.sup.3                                                                10.5                                       30* 84.945                                                                             0.050                                                                              15.000                                                                             0.005                                                                              112     9.4                                                                               7.0 × 10.sup.3                                                                8.0                                        31* 84.750                                                                             0.050                                                                              15.000                                                                             0.200                                                                              116     10.2                                                                              8.0 × 10.sup.3                                                                9.2                                        32* 83.950                                                                             0.050                                                                              15.000                                                                             1.000                                                                              137     10.3                                                                              9.0 × 10.sup.3                                                                9.7                                        33* 74.950                                                                             0.050                                                                              15.000                                                                             10.000                                                                             189     9.0                                                                               7.0 × 10.sup.3                                                                12.6                                       34* 69.950                                                                             0.050                                                                              15.000                                                                             15.000                                                                             212     8.7                                                                               4.0 × 10.sup.3                                                                23.4                                       __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 7

SrTiO₃, very small amount of Nb₂ O₅ which was existing from initial stage of material (contents of Nb₂ O₅ of the material used in the present example was 0.050 mol %), Dy₂ O₃ as oxide of metal for accelerating semiconductorization and NiO as an element to improve non-linearity are formed, reduced and fired, and oxidated in the similar operation as that of the above-mentioned EXAMPLE 5. Results obtained by measuring in the similar condition as that of the above-mentioned of the characteristics of devices thus obtained were shown in TABLE 7.

                                      TABLE 7                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                      Characteristics                                            No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Dy.sub.2 O.sub.3                                                                   NiO V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                           tan δ (%)                            __________________________________________________________________________     1*  99.945                                                                             0.050                                                                              0   0.005                                                                              100     1.0                                                                               4.0 × 10.sup.3                                                                40.4                                       2*  99.750                                                                             0.050                                                                              0   0.200                                                                              92      1.2                                                                               4.0 × 10.sup.3                                                                35.9                                       3*  98.950                                                                             0.050                                                                              0   1.000                                                                              89      1.3                                                                               5.0 × 10.sup.3                                                                30.2                                       4*  89.950                                                                             0.050                                                                              0   10.000                                                                             64      1.7                                                                               7.0 × 10.sup.3                                                                26.0                                       5*  99.945                                                                             0.050                                                                              0.005                                                                              0   41      3.2                                                                               6.0 × 10.sup.3                                                                9.8                                        6   99.940                                                                             0.050                                                                              0.005                                                                              0.005                                                                              80      6.1                                                                               9.0 × 10.sup.3                                                                6.4                                        7   99.745                                                                             0.050                                                                              0.005                                                                              0.200                                                                              62      9.4                                                                               1.0 × 10.sup.4                                                                3.5                                        8   98.945                                                                             0.050                                                                              0.005                                                                              1.000                                                                              46      10.2                                                                              1.4 × 10.sup.4                                                                2.9                                        9   89.945                                                                             0.050                                                                              0.005                                                                              10.000                                                                             31      10.3                                                                              1.6 × 10.sup.4                                                                3.8                                        10* 84.945                                                                             0.050                                                                              0.005                                                                              15.000                                                                             35      10.7                                                                              1.9 × 10.sup.4                                                                8.0                                        11* 99.750                                                                             0.050                                                                              0.200                                                                              0   36      5.1                                                                               7.0 × 10.sup.3                                                                6.7                                        12  99.745                                                                             0.050                                                                              0.200                                                                              0.005                                                                              85      7.4                                                                               1.1 × 10.sup.4                                                                5.4                                        13  99.550                                                                             0.050                                                                              0.200                                                                              0.200                                                                              70      10.1                                                                              1.7 × 10.sup.4                                                                3.8                                        14  98.750                                                                             0.050                                                                              0.200                                                                              1.000                                                                              56      10.3                                                                              1.9 × 10.sup.4                                                                2.6                                        15  89.750                                                                             0.050                                                                              0.200                                                                              10.000                                                                             49      11.4                                                                              2.0 × 10.sup.4                                                                2.7                                        16* 84.750                                                                             0.050                                                                              0.200                                                                              15.000                                                                             43      11.1                                                                              2.5 × 10.sup.4                                                                8.8                                        17* 98.950                                                                             0.050                                                                              1.000                                                                              0   33      6.0                                                                               8.0 × 10.sup.3                                                                8.0                                        18  98.945                                                                             0.050                                                                              1.000                                                                              0.005                                                                              71      9.1                                                                               1.9 × 10.sup.4                                                                5.1                                        19  98.750                                                                             0.050                                                                              1.000                                                                              0.200                                                                              62      10.7                                                                              2.0 × 10.sup.4                                                                3.0                                        20  97.950                                                                             0.050                                                                              1.000                                                                              1.000                                                                              51      11.1                                                                              2.5 × 10.sup.4                                                                2.6                                        21  88.950                                                                             0.050                                                                              1.000                                                                              10.000                                                                             47      12.2                                                                              2.7 × 10.sup.4                                                                2.8                                        22* 83.950                                                                             0.050                                                                              1.000                                                                              15.000                                                                             46      12.6                                                                              2.7 × 10.sup.4                                                                10.4                                       23* 89.950                                                                             0.050                                                                              10.000                                                                             0   42      6.4                                                                               5.0 × 10.sup.3                                                                9.4                                        24  89.945                                                                             0.050                                                                              10.000                                                                             0.005                                                                              64      10.4                                                                              1.8 × 10.sup.4                                                                4.8                                        25  89.750                                                                             0.050                                                                              10.000                                                                             0.200                                                                              61      10.9                                                                              2.0 × 10.sup.4                                                                3.0                                        26  88.950                                                                             0.050                                                                              10.000                                                                             1.000                                                                              58      11.0                                                                              2.2 × 10.sup.4                                                                2.9                                        27  79.950                                                                             0.050                                                                              10.000                                                                             10.000                                                                             52      10.8                                                                              1.9 × 10.sup.4                                                                3.6                                        28* 74.950                                                                             0.050                                                                              10.000                                                                             15.000                                                                             60      9.2                                                                               1.5 × 10.sup.4                                                                14.1                                       29* 84.950                                                                             0.050                                                                              15.000                                                                             0   85      5.0                                                                               7.0 × 10.sup.3                                                                10.5                                       30* 84.945                                                                             0.050                                                                              15.000                                                                             0.005                                                                              82      9.4                                                                               7.0 × 10.sup.3                                                                9.1                                        31* 84.750                                                                             0.050                                                                              15.000                                                                             0.200                                                                              67      10.3                                                                              8.0 × 10.sup.3                                                                8.9                                        32* 83.950                                                                             0.050                                                                              15.000                                                                             1.000                                                                              64      9.1                                                                               9.0 × 10.sup.3                                                                9.2                                        33* 74.950                                                                             0.050                                                                              15.000                                                                             10.000                                                                             79      8.6                                                                               7.0 × 10.sup.3                                                                10.8                                       34* 69.950                                                                             0.050                                                                              15.000                                                                             15.000                                                                             135     6.2                                                                               7.0 × 10.sup.3                                                                23.1                                       __________________________________________________________________________      *Comparison sample                                                       

As shown by EXAMPLEs 5 through 7, in a case Dy₂ O₃ with its added value of 0.005-10.000 mol % and small amount of Nb₂ O₅ contributes to reduce specific resistance of the reduced fired body, and by re-firing in air it shows baristor characteristics.

Herein, the amount of Nb₂ O₅ is that of impurity naturally included in starting material TiO₂, and is in a range of 0.001-0.200 mol % as a result of analysis.

Though for semiconductorization of SrTiO₃, Dy₂ O₃ is effective, the effect of Dy₂ O₃ is not damaged even in the case wherein Nb₂ O₅ is contained at the same time. Accordingly, even when Dy₂ O₃ and Nb₂ O₅ are used at the same time as accelerating agent for semiconductorization, it is possible to produce the baristor characteristics.

However, in the case when Dy₂ O₃ and Nb₂ O₅ only are added, the electric barrier formed at the grain boundaries is low, and the baristor characteristics are relatively small.

Therefore, when such additive as CaO, ZrO₂, NiO, Ga₂ O₃, or the like is added, the added substance is segregated at the crystal granule boundaries during the reducing firing, and by re-firing the air these additives contribute to make the crystal grain boundaries in high resistance, and the baristor characteristics become greater.

Besides, since only the crystal grain boundaries only becomes high resistance, capacitance characteristic is presented between crystal grain-crystal grain boundary-crystal grain.

Accordingly, by adding Dy₂ O₃, Nb₂ O₅ and CaO, ZrO₂, NiO, to SrTiO₃, it is possible to provide characteristics combining the baristor characteristics and the capacitance characteristics. The case such effect is presented is within a range that Dy₂ O₃ is 0.005-10.000 mol %, Nb₂ O₅ is 0.001-0.200 mol %, CaO, ZrO₂, NiO, or Ga₂ O₃ or is 0.005-10.000 mol %.

Though in the above-mentioned EXAMPLEs 5-7, the cases where an additive is added in a single one, it was confirmed that even when in place of the above-mentioned, an oxide of Cd, In, Ba, Cs, Sn, W, Fe, Pt, Tl, Si, Be, Li, Ir, Os, Hf and Ru as single one in a range of the above-mentioned predetermined amount was added, the similar effect was obtained.

Besides, it was confirmed that the same effect was obtained even when two kinds or more of oxides of these Ca, Cd, In, Ba, Cs, Zr, Sn, W, Ni, Fe, Pt, Tl, Si, Be, Li, Ir, Os, Hf and Ru were used in a manner that total added amount is within the above-mentioned range.

By using elements 7 made by providing electrodes by conductive material such as Ag on the sintered body obtained as above and a coil 8, a noise filter shown in FIG. 4 is constituted, and by impressing noise input A shown in FIG. 5 thereon, a noise output B was obtained.

As is obvious from this, the noise is satisfactorily eliminated, and besides, number of components decreases by combination of the element unit and the coil, enabling miniaturization.

EXAMPLE 8

After measuring SrTiO₃, Ta₂ O₅ and CdO to become composition ratios shown in the below-mentioned TABLE 8, they were mixed in wet method in a ball mill or the like for 6 hours, and dried, and thereafter calcinated at 1000°-1250° C. in the air for 1-5 hours. Thereafter, it was ground in wet method by ball mill or the like for 4 hours, and dried, and subsequently, after granulating adding 8 wt % of an organic binder (for instance, polyvinylalcohol), press-formed into a shape of disc of 8.0 (mm)φ×1.0 (mm)t with forming pressure of about 1.0 t/cm². The formed body was fired for 1-6 hours in a reducing atmosphere (for instance, N₂ :H₂ =10:1) and at 1300°-1450° C. Specific resistance of the fired body thus obtained was averagely 0.1-0.8 Ω.cm, and average granule size was 20-50 μm. Nextly, the above-mentioned fired body was baked in the air for 0.5-5 hours at 1000°-1300° C. to obtain a sintered body 4 of FIG. 3. And both faces of the above-mentioned sintered body 4 are ground by using an abrasive such as SiC, and electrodes 5, 6 are formed by using conductive metal such as Ag thereon. Sizes of the electrodes 5, 6 are circle of 5.0 (mm)φ.

Characteristics of the devices thus obtained are shown in TABLE 8. With respect to assesment of barristor element thus obtained, they were made in the same condition as EXAMPLE 1.

                                      TABLE 8                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Ta.sub.2 O.sub.5                                                                    CdO V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              80      1.0                                                                               4.0 × 10.sup.3                                                                35.2                                          2*  99.800                                                                             0    0.200                                                                              85      1.3                                                                               4.0 × 10.sup.3                                                                36.3                                          3*  99.000                                                                             0    1.000                                                                              101     1.6                                                                               5.0 × 10.sup.3                                                                43.1                                          4*  90.000                                                                             0    10.000                                                                             174     2.0                                                                               7.0 × 10.sup.3                                                                57.6                                          5*  99.995                                                                             0.005                                                                               0   78      3.3                                                                               5.0 × 10.sup.3                                                                8.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              60      8.8                                                                               7.0 × 10.sup.3                                                                6.5                                           7   99.795                                                                             0.005                                                                               0.200                                                                              51      9.9                                                                               1.4 × 10.sup.4                                                                3.7                                           8   98.995                                                                             0.005                                                                               1.000                                                                              57      11.6                                                                              1.7 × 10.sup.4                                                                4.2                                           9   89.995                                                                             0.005                                                                               10.000                                                                             60      13.9                                                                              1.9 × 10.sup.4                                                                4.5                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             73      12.5                                                                              1.4 × 10.sup.4                                                                9.7                                           11* 99.800                                                                             0.200                                                                               0   72      4.3                                                                               7.0 × 10.sup.3                                                                5.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              53      9.5                                                                               1.2 × 10.sup.4                                                                2.2                                           13  99.600                                                                             0.200                                                                               0.200                                                                              39      11.3                                                                              1.9 × 10.sup.4                                                                2.7                                           14  98.800                                                                             0.200                                                                               1.000                                                                              43      14.3                                                                              2.0 × 10.sup.4                                                                3.2                                           15  89.800                                                                             0.200                                                                               10.000                                                                             54      15.1                                                                              1.8 × 10.sup.4                                                                4.4                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             75      15.0                                                                              1.2 × 10.sup.4                                                                9.5                                           17* 99.000                                                                             1.000                                                                               0   69      5.5                                                                               9.0 × 10.sup.3                                                                7.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              41      11.9                                                                              2.3 × 10.sup.4                                                                2.6                                           19  98.800                                                                             1.000                                                                               0.200                                                                              32      14.2                                                                              2.8 × 10.sup.4                                                                3.8                                           20  98.000                                                                             1.000                                                                               1.000                                                                              39      18.4                                                                              2.4 × 10.sup.4                                                                3.7                                           21  89.000                                                                             1.000                                                                               10.000                                                                             48      19.0                                                                              1.8 × 10.sup.4                                                                4.4                                           22* 84.000                                                                             1.000                                                                               15.000                                                                             77      19.5                                                                              1.7 × 10.sup.4                                                                10.8                                          23* 90.000                                                                             10.000                                                                              0   61      6.3                                                                               9.0 × 10.sup.3                                                                8.4                                           24  89.995                                                                             10.000                                                                              0.005                                                                              40      13.0                                                                              1.7 × 10.sup.4                                                                3.4                                           25  89.800                                                                             10.000                                                                              0.200                                                                              31      14.9                                                                              2.3 × 10.sup.4                                                                3.7                                           26  89.000                                                                             10.000                                                                              1.000                                                                              42      16.9                                                                              1.9 × 10.sup.4                                                                4.4                                           27  80.000                                                                             10.000                                                                              10.000                                                                             56      18.1                                                                              1.8 × 10.sup.4                                                                4.2                                           28* 75.000                                                                             10.000                                                                              15.000                                                                             97      17.8                                                                              1.5 × 10.sup.4                                                                12.9                                          29* 85.000                                                                             15.000                                                                              0   74      6.6                                                                               7.0 × 10.sup.3                                                                9.7                                           30* 84.995                                                                             15.000                                                                              0.005                                                                              62      12.0                                                                              1.2 × 10.sup.4                                                                6.3                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              60      13.2                                                                              1.2 × 10.sup.4                                                                7.2                                           32* 84.000                                                                             15.000                                                                              1.000                                                                              69      15.8                                                                              9.0 × 10.sup.3                                                                10.6                                          33* 75.000                                                                             15.000                                                                              10.000                                                                             82      13.6                                                                              6.0 × 10.sup.3                                                                14.6                                          34* 70.000                                                                             15.000                                                                              15.000                                                                             124     8.8                                                                               4.0 × 10.sup.3                                                                22.7                                          __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 9

SrTiO₃, Ta₂ O₅ and BaO are made in composition ratios shown in Table 9, and mixing, forming and firing are made in the similar operations as those of the above-mentioned EXAMPLE 8, and measured results made under the similar condition are shown in Table 9.

                                      TABLE 9                                      __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Ta.sub.2 O.sub.5                                                                    BaO V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              79      1.0                                                                               4.0 × 10.sup.3                                                                34.4                                          2*  99.800                                                                             0    0.200                                                                              83      1.5                                                                               4.0 × 10.sup.3                                                                35.4                                          3*  99.000                                                                             0    1.000                                                                              100     1.7                                                                               5.0 × 10.sup.3                                                                41.5                                          4*  90.000                                                                             0    10.000                                                                             165     2.1                                                                               7.0 × 10.sup.3                                                                46.3                                          5*  99.995                                                                             0.005                                                                               0   78      3.3                                                                               5.0 × 10.sup.3                                                                8.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              60      8.6                                                                               7.0 × 10.sup.3                                                                6.3                                           7   99.795                                                                             0.005                                                                               0.200                                                                              49      9.7                                                                               1.5 × 10.sup.4                                                                3.1                                           8   98.995                                                                             0.005                                                                               1.000                                                                              55      10.6                                                                              1.7 × 10.sup.4                                                                3.8                                           9   89.995                                                                             0.005                                                                               10.000                                                                             58      12.9                                                                              2.0 × 10.sup.4                                                                4.9                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             72      12.5                                                                              1.4 × 10.sup.4                                                                9.2                                           11* 99.800                                                                             0.200                                                                               0   72      4.3                                                                               7.0 × 10.sup.3                                                                5.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              53      9.3                                                                               1.6 × 10.sup.4                                                                2.7                                           13  99.600                                                                             0.200                                                                               0.200                                                                              37      10.3                                                                              2.4 × 10.sup.4                                                                2.5                                           14  98.800                                                                             0.200                                                                               1.000                                                                              43      13.3                                                                              2.5 × 10.sup.4                                                                2.0                                           15  89.800                                                                             0.200                                                                               10.000                                                                             51      14.1                                                                              2.0 × 10.sup.4                                                                3.2                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             70      15.8                                                                              1.8 × 10.sup.4                                                                8.7                                           17* 99.000                                                                             1.000                                                                               0   69      5.5                                                                               9.0 × 10.sup.3                                                                7.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              40      11.7                                                                              2.4 × 10.sup.4                                                                2.8                                           19  98.800                                                                             1.000                                                                               0.200                                                                              23      13.6                                                                              2.8 × 10.sup.4                                                                2.7                                           20  98.000                                                                             1.000                                                                               1.000                                                                              36      16.2                                                                              2.5 × 10.sup.4                                                                3.8                                           21  89.00                                                                              1.000                                                                               10.000                                                                             43      18.3                                                                              2.1 × 10.sup.4                                                                4.1                                           22* 84.000                                                                             1.000                                                                               15.00                                                                              75      18.7                                                                              1.4 × 10.sup.4                                                                10.5                                          23* 90.000                                                                             10.000                                                                              0   61      6.3                                                                               9.0 × 10.sup.3                                                                8.4                                           24  89.995                                                                             10.000                                                                              0.000                                                                              39      13.5                                                                              1.8 × 10.sup.4                                                                3.7                                           25  89.800                                                                             10.000                                                                              0.200                                                                              21      15.2                                                                              2.3 × 10.sup.4                                                                3.6                                           26  89.000                                                                             10.000                                                                              1.000                                                                              33      17.3                                                                              2.0 × 10.sup.4                                                                3.9                                           27  80.000                                                                             10.000                                                                              10.000                                                                             45      20.0                                                                              1.8 × 10.sup.4                                                                7.1                                           28* 75.000                                                                             15.000                                                                              15.00                                                                              79      19.5                                                                              1.7 × 10.sup.4                                                                11.3                                          29* 85.000                                                                             0    0   74      6.6                                                                               7.0 × 10.sup.3                                                                9.7                                           30* 84.995                                                                             15.000                                                                              0.005                                                                              51      12.5                                                                              1.2 × 10.sup.4                                                                5.1                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              50      13.7                                                                              1.3 × 10.sup.4                                                                5.4                                           32* 84.000                                                                             15.000                                                                              1.000                                                                              54      16.7                                                                              9.0 × 10.sup.3                                                                6.4                                           33* 75.000                                                                             15.000                                                                              10.000                                                                             79      14.5                                                                              7.0 × 10.sup.3                                                                8.1                                           34* 70.000                                                                             15.000                                                                              15.000                                                                             112     9.6                                                                               4.0 × 10.sup.3                                                                15.2                                          __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 10

SrTiO₃, Ta₂ O₅ and La₂ O₃ are made in composition ratios shown in Table 10, and mixing, forming and firing are made in the similar operations as those of the above-mentioned EXAMPLE 8, and measured results made under the similar condition are shown in Table 10.

                                      TABLE 10                                     __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Ta.sub.2 O.sub.5                                                                    La.sub.2 O.sub.3                                                                   V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              90     1.0 4.0 × 10.sup.3                                                                36.4                                          2*  99.800                                                                             0    0.200                                                                              96     1.3 4.0 × 10.sup.3                                                                39.2                                          3*  99.000                                                                             0    1.000                                                                              112    1.4 6.0 × 10.sup.3                                                                41.5                                          4*  90.000                                                                             0    10.000                                                                             184    1.9 8.0 × 10.sup.3                                                                56.9                                          5*  99.995                                                                             0.005                                                                               0   78     3.3 5.0 × 10.sup.3                                                                8.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              70     9.1 7.0 × 10.sup.3                                                                5.0                                           7   99.795                                                                             0.005                                                                               0.200                                                                              57     9.3 1.0 × 10.sup.4                                                                3.4                                           8   98.795                                                                             0.005                                                                               1.000                                                                              61     10.8                                                                               1.3 × 10.sup.4                                                                3.4                                           9   89.995                                                                             0.005                                                                               10.000                                                                             75     11.4                                                                               1.7 × 10.sup.4                                                                4.5                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             79     11.3                                                                               2.0 × 10.sup.4                                                                8.9                                           11* 99.800                                                                             0.200                                                                               0   72     4.3 7.0 × 10.sup.3                                                                5.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              63     9.6 1.0 × 10.sup.4                                                                2.5                                           13  99.600                                                                             0.200                                                                               0.200                                                                              49     11.5                                                                               1.8 × 10.sup.4                                                                2.4                                           14  98.800                                                                             0.200                                                                               1.000                                                                              54     14.6                                                                               2.0 × 10.sup.4                                                                3.2                                           15  89.800                                                                             0.200                                                                               10.000                                                                             69     15.3                                                                               2.6 × 10.sup.4                                                                4.6                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             85     15.1                                                                               2.7 × 10.sup.4                                                                8.5                                           17* 99.000                                                                             1.000                                                                               0   69     5.5 9.0 × 10.sup.3                                                                7.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              52     12.2                                                                               1.0 × 10.sup.4                                                                2.5                                           19  98.800                                                                             1.000                                                                               0.200                                                                              43     14.6                                                                               1.7 × 10.sup.4                                                                3.7                                           20  98.000                                                                             1.000                                                                               1.000                                                                              53     18.9                                                                               2.1 × 10.sup.4                                                                3.1                                           21  89.000                                                                             1.000                                                                               10.000                                                                             60     19.0                                                                               2.3 × 10.sup.4                                                                3.2                                           22* 84.000                                                                             1.000                                                                               15.000                                                                             89     19.2                                                                               1.1 × 10.sup.4                                                                9.8                                           23* 90.000                                                                             10.000                                                                              0   61     6.3 9.0 × 10.sup.3                                                                8.4                                           24  89.995                                                                             10.000                                                                              0.005                                                                              51     12.7                                                                               1.7 × 10.sup.4                                                                3.2                                           25  89.800                                                                             10.000                                                                              0.200                                                                              42     14.3                                                                               2.2 × 10.sup.4                                                                3.5                                           26  89.000                                                                             10.000                                                                              1.000                                                                              55     15.9                                                                               2.6 × 10.sup.4                                                                4.8                                           27  80.000                                                                             10.000                                                                              10.000                                                                             67     17.8                                                                               2.3 × 10.sup.4                                                                4.3                                           28* 75.000                                                                             10.000                                                                              15.000                                                                             110    17.5                                                                               1.9 × 10.sup.4                                                                13.0                                          29* 85.000                                                                             15.000                                                                              0   74     6.6 7.0 × 10.sup. 3                                                               9.7                                           30* 84.995                                                                             15.000                                                                              0.005                                                                              72     11.0                                                                               8.0 × 10.sup.3                                                                7.9                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              71     12.1                                                                               8.0 × 10.sup.3                                                                8.8                                           32* 84.000                                                                             15.000                                                                              1.000                                                                              78     14.0                                                                               9.0 × 10.sup.3                                                                10.7                                          33* 75.000                                                                             15.000                                                                              10.000                                                                             97     12.2                                                                               7.0 × 10.sup.3                                                                15.2                                          34* 70.000                                                                             15.000                                                                              15.000                                                                             136    8.3 4.0 × 10.sup.3                                                                24.6                                          __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 11

SrTiO₃, Ta₂ O₅ and Y₂ O₃ are made in composition ratios shown in Table 11, and mixing, forming and firing are made in the similar operations as those of the above-mentioned EXAMPLE 8, and measured results made under the similar condition are shown in Table 11.

                                      TABLE 11                                     __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Ta.sub.2 O.sub.5                                                                    Y.sub.2 O.sub.3                                                                    V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              81      1.0                                                                               4.0 × 10.sup.3                                                                34.6                                          2*  99.800                                                                             0    0.200                                                                              106     1.3                                                                               4.0 × 10.sup.3                                                                38.2                                          3*  99.000                                                                             0    1.000                                                                              160     1.4                                                                               6.0 × 10.sup.3                                                                40.5                                          4*  90.000                                                                             0    10.000                                                                             172     1.7                                                                               7.0 × 10.sup.3                                                                46.8                                          5*  99.995                                                                             0.005                                                                               0   78      3.3                                                                               5.0 × 10.sup.3                                                                8.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              87      9.0                                                                               1.0 × 10.sup.4                                                                5.3                                           7   99.795                                                                             0.005                                                                               0.200                                                                              81      9.4                                                                               1.6 × 10.sup.4                                                                3.8                                           8   98.995                                                                             0.005                                                                               1.000                                                                              86      10.9                                                                              1.9 × 10.sup.4                                                                2.9                                           9   89.995                                                                             0.005                                                                               10.000                                                                             95      11.3                                                                              2.6 × 10.sup.4                                                                2.2                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             107     11.5                                                                              2.1 × 10.sup.4                                                                7.3                                           11* 99.800                                                                             0.200                                                                               0   72      4.3                                                                               7.0 × 10.sup.3                                                                5.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              70      9.2                                                                               1.5 × 10.sup.4                                                                3.5                                           13  99.600                                                                             0.200                                                                               0.200                                                                              59      10.7                                                                              2.6 × 10.sup.4                                                                2.0                                           14  98.800                                                                             0.200                                                                               1.000                                                                              52      13.7                                                                              3.0 × 10.sup.4                                                                2.7                                           15  89.800                                                                             0.200                                                                               10.000                                                                             61      15.2                                                                              3.1 × 10.sup.4                                                                2.9                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             70      15.0                                                                              2.7 × 10.sup.4                                                                8.7                                           17* 99.000                                                                             1.000                                                                               0   69      5.5                                                                               9.0 × 10.sup.3                                                                7.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              67      12.1                                                                              1.6 × 10.sup.4                                                                2.8                                           19  98.800                                                                             1.000                                                                               0.200                                                                              54      13.9                                                                              2.2 × 10.sup.4                                                                2.1                                           20  98.000                                                                             1.000                                                                               1.000                                                                              58      18.2                                                                              2.7 × 10.sup.4                                                                2.9                                           21  89.000                                                                             1.000                                                                               10.000                                                                             65      18.9                                                                              2.3 × 10.sup.4                                                                3.9                                           22* 84.000                                                                             1.000                                                                               15.000                                                                             98      19.1                                                                              1.1 × 10.sup.4                                                                8.6                                           23* 90.000                                                                             10.000                                                                              0   61      6.3                                                                               9.0 × 10.sup.3                                                                8.4                                           24  89.995                                                                             10.000                                                                              0.005                                                                              57      11.7                                                                              1.7 × 10.sup.4                                                                3.8                                           25  89.800                                                                             10.000                                                                              0.200                                                                              48      13.4                                                                              2.0 × 10.sup.4                                                                2.4                                           26  89.000                                                                             10.000                                                                              1.000                                                                              56      15.0                                                                              2.5 × 10.sup.4                                                                3.8                                           27  80.000                                                                             10.000                                                                              10.000                                                                             73      17.1                                                                              2.5 × 10.sup.4                                                                3.9                                           28* 75.000                                                                             10.000                                                                              15.000                                                                             109     17.0                                                                              1.9 × 10.sup.4                                                                9.3                                           29* 85.000                                                                             15.000                                                                              0   74      6.6                                                                               7.0 × 10.sup. 3                                                               9.7                                           30* 84.995                                                                             15.000                                                                              0.005                                                                              70      10.9                                                                              8.0 × 10.sup.3                                                                7.7                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              68      11.5                                                                              9.0 × 10.sup.3                                                                8.4                                           32* 84.000                                                                             15.000                                                                              1.000                                                                              78      13.7                                                                              9.0 × 10.sup.3                                                                10.6                                          33* 75.000                                                                             15.000                                                                              10.000                                                                             101     10.2                                                                              8.0 × 10.sup.3                                                                13.6                                          34* 70.000                                                                             15.000                                                                              15.000                                                                             139     7.3                                                                               5.0 × 10.sup.3                                                                23.9                                          __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 12

SrTiO₃, Ta₂ O₅ and Gd₂ O₃ are made in composition ratios shown in Table 12, and mixing, forming and firing are made in the similar operations as those of the above-mentioned EXAMPLE 8, and measured results made under the similar condition are shown in Table 12.

                                      TABLE 12                                     __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                   Characteristics                                               No. SrTiO.sub.3                                                                        Ta.sub.2 O.sub.5                                                                    Gd.sub.2 O.sub.3                                                                   V.sub.1 mA (V/mm)                                                                      α                                                                           ε                                                                           tan δ (%)                               __________________________________________________________________________     1*  99.995                                                                             0    0.005                                                                              101     1.0                                                                               4.0 × 10.sup.3                                                                44.6                                          2*  99.800                                                                             0    0.200                                                                              105     1.6                                                                               4.0 × 10.sup.3                                                                39.1                                          3*  99.000                                                                             0    1.000                                                                              173     2.0                                                                               7.0 × 10.sup.3                                                                31.3                                          4*  90.000                                                                             0    10.000                                                                             213     2.4                                                                               7.0 × 10.sup.3                                                                26.0                                          5*  99.995                                                                             0.005                                                                               0   78      3.3                                                                               5.0 × 10.sup.3                                                                8.6                                           6   99.990                                                                             0.005                                                                               0.005                                                                              82      6.7                                                                               7.0 × 10.sup.3                                                                4.5                                           7   99.795                                                                             0.005                                                                               0.200                                                                              80      9.0                                                                               1.1 × 10.sup.4                                                                3.6                                           8   98.995                                                                             0.005                                                                               1.000                                                                              87      13.7                                                                              1.5 × 10.sup.4                                                                2.7                                           9   89.995                                                                             0.005                                                                               10.000                                                                             98      15.0                                                                              1.9 × 10.sup.4                                                                3.2                                           10* 84.995                                                                             0.005                                                                               15.000                                                                             112     15.5                                                                              2.2 × 10.sup.4                                                                6.8                                           11* 99.800                                                                             0.200                                                                               0   72      4.3                                                                               7.0 × 10.sup.3                                                                5.1                                           12  99.795                                                                             0.200                                                                               0.005                                                                              80      7.1                                                                               1.1 × 10.sup.4                                                                3.0                                           13  99.600                                                                             0.200                                                                               0.200                                                                              72      11.0                                                                              1.6 × 10.sup.4                                                                2.5                                           14  98.800                                                                             0.200                                                                               1.000                                                                              81      14.5                                                                              2.0 × 10.sup.4                                                                2.0                                           15  89.800                                                                             0.200                                                                               10.000                                                                             89      15.2                                                                              2.8 × 10.sup.4                                                                2.7                                           16* 84.800                                                                             0.200                                                                               15.000                                                                             98      15.9                                                                              2.9 × 10.sup.4                                                                7.4                                           17* 99.000                                                                             1.000                                                                               0   69      5.5                                                                               9.0 × 10.sup.3                                                                7.0                                           18  98.995                                                                             1.000                                                                               0.005                                                                              87      10.1                                                                              1.6 × 10.sup.4                                                                2.5                                           19  98.800                                                                             1.000                                                                               0.200                                                                              63      12.3                                                                              1.7 × 10.sup.4                                                                2.3                                           20  98.000                                                                             1.000                                                                               1.000                                                                              68      13.2                                                                              2.3 × 10.sup.4                                                                2.9                                           21  89.000                                                                             1.000                                                                               10.000                                                                             74      14.9                                                                              1.9 × 10.sup.4                                                                3.1                                           22* 84.000                                                                             1.000                                                                               15.000                                                                             103     12.3                                                                              1.4 × 10.sup.4                                                                8.6                                           23* 90.000                                                                             10.000                                                                              0   61      6.3                                                                               9.0 × 10.sup.3                                                                8.4                                           24  89.995                                                                             10.000                                                                              0.005                                                                              65      12.5                                                                              1.8 × 10.sup.4                                                                3.6                                           25  89.800                                                                             10.000                                                                              0.200                                                                              57      13.1                                                                              2.3 × 10.sup.4                                                                2.0                                           26  89.000                                                                             10.000                                                                              1.000                                                                              68      13.9                                                                              2.6 × 10.sup.4                                                                3.5                                           27  80.000                                                                             10.000                                                                              10.000                                                                             83      12.8                                                                              2.5 × 10.sup.4                                                                3.7                                           28* 75.000                                                                             10.000                                                                              15.000                                                                             114     10.8                                                                              2.0 × 10.sup.4                                                                9.1                                           29* 85.000                                                                             15.000                                                                              0   74      6.6                                                                               7.0 × 10.sup. 3                                                               9.7                                           30* 84.995                                                                             15.000                                                                              0.005                                                                              84      8.4                                                                               8.0 × 10.sup.3                                                                6.6                                           31* 84.800                                                                             15.000                                                                              0.200                                                                              79      8.0                                                                               9.0 × 10.sup.3                                                                8.3                                           32* 84.000                                                                             15.000                                                                              1.000                                                                              85      7.6                                                                               9.0 × 10.sup.3                                                                10.2                                          33* 75.000                                                                             15.000                                                                              10.000                                                                             114     7.5                                                                               8.0 × 10.sup.3                                                                14.6                                          34* 70.000                                                                             15.000                                                                              15.000                                                                             148     4.6                                                                               5.0 × 10.sup.3                                                                25.7                                          __________________________________________________________________________      *Comparison sample                                                       

As shown by EXAMPLEs 8 through 12, Ta₂ O₅ with its added value in a range of 0.005-10.000 mol %, contributes to reduce specific resistance of the reduced fired body, and by re-firing in air it shows baristor characteristics.

This is because that granules and grain boundaries of fired body obtained by the reduced firing is of low resistances, and by re-firing in the air only crystal boundaries become to high resistance thereby forming electric barriers.

However, when only Ta₂ O₅ is added, the electric barrier formed at the grain boundaries are small, and the baristor characteristics are relatively small.

Accordingly, by adding additives such as CdO, BaO, La₂ O₃, Y₂ O₃, Gd₂ O₃, the additive is segregated at the grain boundaries during the reduced firing, and by re-firing in the air such additive forms large electric barrier at the grain boundary, thereby making the baristor characteristics large.

And, by making the crystal grain boundary only in high resistance, capacitance characteristics is presented between crystal granule--crystal grain boundaries--crystal granules.

Accordingly, by adding Ta₂ O₅ and additive S such as CdO, BaO, La₂ O₃, Y₂ O₃, Gd₂ O₃, to SrTiO₃, it is possible to provide a characteristic combining the aristor characteristics and the capacitance characteristics.

The case such effect is presented is within a range that Ta₂ O₅ is 0.005-10.000 mol %, CdO, BaO, La₂ O₃, Y₂ O₃, Gd₂ O₃, are 0.005-10.000 mol %.

Though in the above-mentioned EXAMPLES 18-24, the elucidation was made for the cases where an additive was added in a single one, it was confirmed that when in place of the above-mentioned, an oxide of Ca, In, Cs, Sn, Sb, W, Pt, Tl, Eu, Tb, Tm, Lu, Th, Ir, Os, Hf and Ru as single one in a range of the above-mentioned predetermined amount was added, the similar effect was obtained.

Besides, it was confirmed that the same effect was obtained even when two kinds or more of oxides of these Ca, Cd, In, Ba, La, Y, Cs, Sn, Sb, W, Pt, Tl, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf and Ru were used so that total added amount is within the above-mentioned range.

EXAMPLE 13

After measuring SrTiO₃, extremely small amount of Nb₂ O₅ which was existing from the initial stage of material (Nb₂ O₅ content in the material used in the present example was 0.050 mol %), Ta₂ O₅ as oxide of metal for acceleration of semiconductorization and CdO as element to improve non-linearity to become composition ratios shown in the below-mentioned TABLE 13, they were mixed and ground and dried, and thereafter calcinated at 1000° C. for 4 hours. Thereafter, it was ground in wet method by ball mill or the like for 4 hours, and dried, and subsequently, after granulating adding 8 wt % of an organic binder (for instance, polyvinylalcohol), press-formed into a shape of disc of 8.0 φ (mm)×1.0 t (mm) with forming pressure of about 1.0 t/cm². The formed body was fired for 4 hours in a reducing atmosphere (for instance, N₂ :H₂ =1:1, flow rate is 1.0 l/min) and at 1350° C. Specific resistance of the fired body thus obtained was averagely 0.3 Ω.cm, and average granule size was 30 μm.

Nextly, the above-mentioned fired body was baked in the air for 2 hours at 1300° C. to obtain a sintered body 4 of FIG. 3. And both faces of the above-mentioned sintered body 4 are ground by using an abrasive such as SiC or the like, as Ag on the ground faces. Sizes of the electrodes 5, 6 are circle of 5.0 φ (mm).

Characteristic of the devices thus obtained are shown in TABLE 13.

                                      TABLE 25                                     __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                      Characteristics                                            No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   CdO V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                           tan δ (%)                            __________________________________________________________________________     1*  99.945                                                                             0.050                                                                              0   0.005                                                                              75      1.0                                                                               4.0 × 10.sup.3                                                                35.2                                       2*  99.750                                                                             0.050                                                                              0   0.200                                                                              80      1.3                                                                               4.0 × 10.sup.3                                                                36.0                                       3*  98.950                                                                             0.050                                                                              0   1.000                                                                              96      1.6                                                                               4.0 × 10.sup.3                                                                44.3                                       4*  89.950                                                                             0.050                                                                              0   10.000                                                                             164     2.1                                                                               5.0 × 10.sup.3                                                                56.7                                       5*  99.945                                                                             0.050                                                                              0.005                                                                              0   80      3.0                                                                               5.0 × 10.sup.3                                                                8.6                                        6   99.940                                                                             0.050                                                                              0.005                                                                              0.005                                                                              65      8.5                                                                               6.0 × 10.sup.3                                                                6.4                                        7   99.745                                                                             0.050                                                                              0.005                                                                              0.200                                                                              56      9.8                                                                               1.3 × 10.sup.4                                                                3.6                                        8   98.945                                                                             0.050                                                                              0.005                                                                              1.000                                                                              62      10.6                                                                              1.3 × 10.sup.4                                                                4.1                                        9   89.945                                                                             0.050                                                                              0.005                                                                              10.000                                                                             65      13.5                                                                              1.7 × 10.sup.4                                                                4.4                                        10* 84.945                                                                             0.050                                                                              0.005                                                                              15.000                                                                             78      11.5                                                                              1.0 × 10.sup.4                                                                9.8                                        11* 99.750                                                                             0.050                                                                              0.200                                                                              0   75      3.4                                                                               5.0 × 10.sup.3                                                                5.2                                        12  99.745                                                                             0.050                                                                              0.200                                                                              0.005                                                                              56      8.9                                                                               1.0 × 10.sup.4                                                                2.3                                        13  99.550                                                                             0.050                                                                              0.200                                                                              0.200                                                                              42      11.0                                                                              1.2 × 10.sup.4                                                                2.8                                        14  98.750                                                                             0.050                                                                              0.200                                                                              1.000                                                                              46      13.1                                                                              1.5 × 10.sup.4                                                                3.0                                        15  89.750                                                                             0.050                                                                              0.200                                                                              10.000                                                                             57      14.1                                                                              1.9 × 10.sup.4                                                                4.5                                        16* 84.750                                                                             0.050                                                                              0.200                                                                              15.000                                                                             78      12.5                                                                              1.1 × 10.sup.4                                                                9.7                                        17* 98.950                                                                             0.050                                                                              1.000                                                                              0   71      4.5                                                                               6.0 × 10.sup.4                                                                6.0                                        18  98.945                                                                             0.050                                                                              1.000                                                                              0.005                                                                              43      10.9                                                                              2.0 × 10.sup.4                                                                2.5                                        19  98.750                                                                             0.050                                                                              1.000                                                                              0.200                                                                              34      13.0                                                                              2.2 × 10.sup.4                                                                3.6                                        20  97.950                                                                             0.050                                                                              1.000                                                                              1.000                                                                              41      16.4                                                                              2.3 × 10.sup.4                                                                3.3                                        21  88.950                                                                             0.050                                                                              1.000                                                                              10.000                                                                             51      18.0                                                                              1.5 × 10.sup.4                                                                4.5                                        22* 83.950                                                                             0.050                                                                              1.000                                                                              15.000                                                                             80      15.9                                                                              1.0 × 10.sup.4                                                                11.0                                       23* 89.950                                                                             0.050                                                                              10.000                                                                             0   61      4.8                                                                               6.0 × 10.sup.3                                                                7.0                                        24  89.945                                                                             0.050                                                                              10.000                                                                             0.005                                                                              41      11.3                                                                              1.2 × 10.sup.4                                                                3.3                                        25  89.750                                                                             0.050                                                                              10.000                                                                             0.200                                                                              32      13.1                                                                              1.7 × 10.sup.4                                                                3.6                                        26  88.950                                                                             0.050                                                                              10.000                                                                             1.000                                                                              43      14.9                                                                              1.9 × 10.sup.4                                                                4.3                                        27  79.950                                                                             0.050                                                                              10.000                                                                             10.000                                                                             57      15.1                                                                              1.7 × 10.sup.4                                                                4.1                                        28* 74.950                                                                             0.050                                                                              10.000                                                                             15.000                                                                             98      12.0                                                                              1.4 × 10.sup.4                                                                13.0                                       29* 84.950                                                                             0.050                                                                              15.000                                                                             0   79      5.1                                                                               5.0 × 10.sup.3                                                                7.9                                        30* 84.945                                                                             0.050                                                                              15.000                                                                             0.005                                                                              67      10.0                                                                              1.1 × 10.sup.4                                                                6.5                                        31* 84.750                                                                             0.050                                                                              15.000                                                                             0.200                                                                              65      10.3                                                                              1.1 × 10.sup.4                                                                7.4                                        32* 83.950                                                                             0.050                                                                              15.000                                                                             1.000                                                                              74      11.8                                                                              1.0 × 10.sup.4                                                                10.9                                       33* 74.950                                                                             0.050                                                                              15.000                                                                             10.000                                                                             90      8.9                                                                               4.0 × 10.sup.3                                                                16.4                                       34* 69.950                                                                             0.050                                                                              15.000                                                                             15.000                                                                             174     6.1                                                                               4.0 × 10.sup.3                                                                27.2                                       __________________________________________________________________________      *Comparative sample                                                      

EXAMPLE 14

SrTiO₃, very small amount of Nb₂ O₅ which was existing from initial stage of material (contents of Nb₂ O₅ of the material used in the present example was 0.050 mol %), Ta₂ O₅ as oxide of metal for accelerating semicondoctorization and BaO as an element to improve non-linearity are formed, reduced and fired, and oxidated in the similar operation as that of the above-mentioned EXAMPLE 13. Results obtained by measuring in the similar condition as that of the above-mentioned of the characteristics of devices thus obtained were shown in TABLE 14.

                                      TABLE 14                                     __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                      Characteristics                                            No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   BaO V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                           tan δ (%)                            __________________________________________________________________________     1*  99.945                                                                             0.050                                                                              0   0.005                                                                              84      1.0                                                                               4.0 × 10.sup.3                                                                35.4                                       2*  99.750                                                                             0.050                                                                              0   0.200                                                                              88      1.4                                                                               4.0 × 10.sup.3                                                                36.4                                       3*  98.950                                                                             0.050                                                                              0   1.000                                                                              105     1.5                                                                               4.0 × 10.sup.3                                                                42.5                                       4*  89.950                                                                             0.050                                                                              0   10.000                                                                             170     1.7                                                                               5.0 × 10.sup.3                                                                47.0                                       5*  99.945                                                                             0.050                                                                              0.005                                                                              0   80      3.0                                                                               5.0 × 10.sup.3                                                                8.6                                        6   99.940                                                                             0.050                                                                              0.005                                                                              0.005                                                                              62      8.6                                                                               7.0 × 10.sup.3                                                                6.3                                        7   99.745                                                                             0.050                                                                              0.005                                                                              0.200                                                                              51      9.8                                                                               9.0 × 10.sup.3                                                                3.4                                        8   98.945                                                                             0.050                                                                              0.005                                                                              1.000                                                                              57      10.6                                                                              1.7 × 10.sup.4                                                                3.9                                        9   89.945                                                                             0.050                                                                              0.005                                                                              10.000                                                                             60      11.9                                                                              1.9 × 10.sup.4                                                                4.8                                        10* 84.945                                                                             0.050                                                                              0.005                                                                              15.000                                                                             72      11.5                                                                              1.4 × 10.sup.4                                                                9.5                                        11* 99.750                                                                             0.050                                                                              0.200                                                                              0   75      3.4                                                                               5 × 10.sup.3                                                                  5.2                                        12  99.745                                                                             0.050                                                                              0.200                                                                              0.005                                                                              56      9.0                                                                               1.4 × 10.sup.4                                                                2.7                                        13  99.550                                                                             0.050                                                                              0.200                                                                              0.200                                                                              39      10.1                                                                              1.6 × 10.sup.4                                                                2.5                                        14  98.750                                                                             0.050                                                                              0.200                                                                              1.000                                                                              45      11.1                                                                              2.0 × 10.sup.4                                                                2.1                                        15  89.750                                                                             0.050                                                                              0.200                                                                              10.000                                                                             54      12.3                                                                              1.8 × 10.sup.4                                                                3.2                                        16* 84.750                                                                             0.050                                                                              0.200                                                                              15.000                                                                             73      13.8                                                                              1.5 × 10.sup.4                                                                8.9                                        17* 98.950                                                                             0.050                                                                              1.000                                                                              0   71      4.5                                                                               6.0 × 10.sup.3                                                                6.0                                        18  98.945                                                                             0.050                                                                              1.000                                                                              0.005                                                                              42      10.7                                                                              1.8 × 10.sup.4                                                                2.8                                        19  98.750                                                                             0.050                                                                              1.000                                                                              0.200                                                                              25      11.7                                                                              2.0 × 10.sup.4                                                                2.7                                        20  97.950                                                                             0.050                                                                              1.000                                                                              1.000                                                                              38      12.6                                                                              2.1 × 10.sup.4                                                                3.8                                        21  88.950                                                                             0.050                                                                              1.000                                                                              10.000                                                                             45      13.3                                                                              1.8 × 10.sup.4                                                                4.1                                        22* 83.950                                                                             0.050                                                                              1.000                                                                              15.000                                                                             80      13.0                                                                              1.5 × 10.sup.4                                                                11.5                                       23* 89.950                                                                             0.050                                                                              10.000                                                                             0   61      4.8                                                                               6.0 × 10.sup.3                                                                7.0                                        24  89.945                                                                             0.050                                                                              10.000                                                                             0.005                                                                              39      10.5                                                                              1.5 × 10.sup.4                                                                3.5                                        25  89.750                                                                             0.050                                                                              10.000                                                                             0.200                                                                              25      11.2                                                                              1.8 × 10.sup.4                                                                3.6                                        26  88.950                                                                             0.050                                                                              10.000                                                                             1.000                                                                              38      12.2                                                                              1.7 × 10.sup.4                                                                3.9                                        27  79.950                                                                             0.050                                                                              10.000                                                                             10.000                                                                             50      13.0                                                                              1.6 × 10.sup.4                                                                7.0                                        28* 74.950                                                                             0.050                                                                              10.000                                                                             15.000                                                                             89      14.1                                                                              1.2 × 10.sup.4                                                                11.7                                       29* 84.950                                                                             0.050                                                                              15.000                                                                             0   79      5.1                                                                               5.0 × 10.sup.3                                                                7.9                                        30* 84.945                                                                             0.050                                                                              15.000                                                                             0.005                                                                              56      10.5                                                                              1.1 × 10.sup.4                                                                5.0                                        31* 84.750                                                                             0.050                                                                              15.000                                                                             0.200                                                                              55      11.7                                                                              1.0 × 10.sup.4                                                                5.2                                        32* 83.950                                                                             0.050                                                                              15.000                                                                             1.000                                                                              59      11.9                                                                              8.0 × 10.sup.3                                                                6.1                                        33* 74.950                                                                             0.050                                                                              15.000                                                                             10.000                                                                             89      11.8                                                                              5.0 × 10.sup.3                                                                7.8                                        34* 69.950                                                                             0.050                                                                              15.000                                                                             15.000                                                                             121     6.1                                                                               4.0 × 10.sup.3                                                                15.0                                       __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 15

SrTiO₃, very small amount of Nb₂ O₅ which was existing from initial stage of material (contents of Nb₂ O₅ of the material used in the present example was 0.050 mol %), Ta₂ O₅ as oxide of metal for accelerating semicondoctorization and La₂ O₃ as an element to improve non-linearity are formed, reduced and fired, and oxidated in the similar operation as that of the above-mentioned EXAMPLE 13. Results obtained by measuring in the similar condition as that of the above-mentioned of the characteristics of devices thus obtained were shown in TABLE 15.

                                      TABLE 15                                     __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                      Characteristics                                            No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   La.sub.2 O.sub.3                                                                   V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                           tan δ (%)                            __________________________________________________________________________     1*  99.945                                                                             0.050                                                                              0   0.005                                                                              90      1.0                                                                               4.0 × 10.sup.3                                                                35.4                                       2*  99.750                                                                             0.050                                                                              0   0.200                                                                              96      1.2                                                                               4.0 × 10.sup.3                                                                39.0                                       3*  98.950                                                                             0.050                                                                              0   1.000                                                                              113     1.3                                                                               5.0 × 10.sup.3                                                                40.5                                       4*  89.950                                                                             0.050                                                                              0   10.000                                                                             186     1.7                                                                               7.0 × 10.sup.3                                                                56.8                                       5*  99.945                                                                             0.050                                                                              0.005                                                                              0   80      3.0                                                                               5.0 × 10.sup.3                                                                8.6                                        6   99.940                                                                             0.050                                                                              0.005                                                                              0.005                                                                              72      8.2                                                                               7.0 × 10.sup.3                                                                5.1                                        7   99.745                                                                             0.050                                                                              0.005                                                                              0.200                                                                              59      8.5                                                                               1.0 × 10.sup.4                                                                3.0                                        8   98.945                                                                             0.050                                                                              0.005                                                                              1.000                                                                              63      9.8                                                                               1.4 × 10.sup.4                                                                3.1                                        9   89.945                                                                             0.050                                                                              0.005                                                                              10.000                                                                             77      10.4                                                                              1.8 × 10.sup.4                                                                4.2                                        10* 84.945                                                                             0.050                                                                              0.005                                                                              15.000                                                                             81      10.3                                                                              1.5 × 10.sup.4                                                                9.8                                        11* 99.750                                                                             0.050                                                                              0.200                                                                              0   75      3.4                                                                               5.0 ×  10.sup.3                                                               5.2                                        12  99.745                                                                             0.050                                                                              0.200                                                                              0.005                                                                              65      8.6                                                                               1.0 × 10.sup.4                                                                3.1                                        13  99.550                                                                             0.050                                                                              0.200                                                                              0.200                                                                              51      10.9                                                                              1.8 × 10.sup.4                                                                2.7                                        14  98.750                                                                             0.050                                                                              0.200                                                                              1.000                                                                              54      13.2                                                                              2.0 × 10.sup.4                                                                3.0                                        15  89.750                                                                             0.050                                                                              0.200                                                                              10.000                                                                             69      14.3                                                                              2.2 × 10.sup.4                                                                3.2                                        16* 84.750                                                                             0.050                                                                              0.200                                                                              15.000                                                                             87      14.0                                                                              2.3 × 10.sup.4                                                                8.4                                        17* 98.950                                                                             0.050                                                                              1.000                                                                              0   71      4.5                                                                               6.0 × 10.sup.3                                                                6.0                                        18  98.945                                                                             0.050                                                                              1.000                                                                              0.005                                                                              53      11.2                                                                              1.0 × 10.sup.4                                                                2.9                                        19  98.750                                                                             0.050                                                                              1.000                                                                              0.200                                                                              45      13.6                                                                              1.6 × 10.sup.4                                                                3.5                                        20  97.950                                                                             0.050                                                                              1.000                                                                              1.000                                                                              55      16.4                                                                              2.0 × 10.sup.4                                                                3.0                                        21  88.950                                                                             0.050                                                                              1.000                                                                              10.000                                                                             62      16.5                                                                              2.1 × 10.sup.4                                                                3.2                                        22* 83.950                                                                             0.050                                                                              1.000                                                                              15.000                                                                             91      17.0                                                                              1.5 × 10.sup.4                                                                9.9                                        23* 89.950                                                                             0.050                                                                              10.000                                                                             0   61      4.8                                                                               6.0 × 10.sup.3                                                                7.0                                        24  89.945                                                                             0.050                                                                              10.000                                                                             0.005                                                                              51      10.7                                                                              1.2 × 10.sup.4                                                                3.2                                        25  89.750                                                                             0.050                                                                              10.000                                                                             0.200                                                                              43      12.3                                                                              1.7 × 10.sup.4                                                                3.5                                        26  88.950                                                                             0.050                                                                              10.000                                                                             1.000                                                                              57      13.9                                                                              2.1 × 10.sup.4                                                                4.8                                        27  79.950                                                                             0.050                                                                              10.000                                                                             10.000                                                                             69      13.8                                                                              2.0 × 10.sup.4                                                                6.1                                        28* 74.950                                                                             0.050                                                                              10.000                                                                             15.000                                                                             120     13.5                                                                              1.8 × 10.sup.4                                                                11.0                                       29* 84.950                                                                             0.050                                                                              15.000                                                                             0   79      5.1                                                                               5.0 × 10.sup.3                                                                7.9                                        30* 84.945                                                                             0.050                                                                              15.000                                                                             0.005                                                                              75      10.0                                                                              8.0 × 10.sup.3                                                                7.5                                        31* 84.750                                                                             0.050                                                                              15.000                                                                             0.200                                                                              74      11.1                                                                              8.0 × 10.sup.3                                                                7.6                                        32* 83.950                                                                             0.050                                                                              15.000                                                                             1.000                                                                              79      12.0                                                                              7.0 × 10.sup.3                                                                8.1                                        33* 74.950                                                                             0.050                                                                              15.000                                                                             10.000                                                                             102     11.2                                                                              7.0 × 10.sup.3                                                                10.2                                       34* 69.950                                                                             0.050                                                                              15.000                                                                             15.000                                                                             143     7.9                                                                               5.0 × 10.sup.3                                                                14.6                                       __________________________________________________________________________      *Comparison sample                                                       

EXAMPLE 16

SrTiO₃, very small amount of Nb₂ O₅ which was existing from initial stage of material (contents of Nb₂ O₅ of the material used in the present example was 0.050 mol %), Ta₂ O₅ as oxide of metal for accelerating semicondoctorization and Y₂ O₃ as an element to improve non-linearity are formed, reduced and fired, and oxidated in the similar operation as that of the above-mentioned EXAMPLE 13. Results obtained by measuring in the similar condition as that of the above-mentioned of the characteristics of devices thus obtained were shown in TABLE 16.

                                      TABLE 16                                     __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                      Characteristics                                            No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   Y.sub.2 O.sub.3                                                                    V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                           tan δ (%)                            __________________________________________________________________________     1*  99.945                                                                             0.050                                                                              0   0.005                                                                              82      1.0                                                                               4.0 × 10.sup.3                                                                35.6                                       2*  99.750                                                                             0.050                                                                              0   0.200                                                                              107     1.3                                                                               4.0 × 10.sup.3                                                                39.2                                       3*  98.950                                                                             0.050                                                                              0   1.000                                                                              161     1.4                                                                               4.0 × 10.sup.3                                                                41.5                                       4*  89.950                                                                             0.050                                                                              0   10.000                                                                             175     1.5                                                                               7.0 × 10.sup.3                                                                47.8                                       5*  99.945                                                                             0.050                                                                              0.005                                                                              0   80      3.0                                                                               5.0 × 10.sup.3                                                                8.6                                        6   99.940                                                                             0.050                                                                              0.005                                                                              0.005                                                                              89      8.0                                                                               1.0 × 10.sup.4                                                                5.3                                        7   99.745                                                                             0.050                                                                              0.005                                                                              0.200                                                                              83      9.0                                                                               1.5 × 10.sup.4                                                                3.8                                        8   98.945                                                                             0.050                                                                              0.005                                                                              1.000                                                                              88      9.4                                                                               1.9 × 10.sup.4                                                                3.4                                        9   89.945                                                                             0.050                                                                              0.005                                                                              10.000                                                                             97      10.9                                                                              2.1 × 10.sup.4                                                                3.0                                        10* 84.945                                                                             0.050                                                                              0.005                                                                              15.000                                                                             111     11.3                                                                              2.0 × 10.sup.4                                                                7.4                                        11* 99.750                                                                             0.050                                                                              0.200                                                                              0   75      3.4                                                                               5.0 ×  10.sup.3                                                               5.2                                        12  99.745                                                                             0.050                                                                              0.200                                                                              0.005                                                                              73      8.2                                                                               1.4 × 10.sup.4                                                                3.6                                        13  99.550                                                                             0.050                                                                              0.200                                                                              0.200                                                                              62      9.9                                                                               1.7 × 10.sup.4                                                                2.8                                        14  98.750                                                                             0.050                                                                              0.200                                                                              1.000                                                                              55      11.7                                                                              2.0 × 10.sup.4                                                                2.5                                        15  89.750                                                                             0.050                                                                              0.200                                                                              10.000                                                                             64      13.2                                                                              2.1 × 10.sup.4                                                                2.9                                        16* 84.750                                                                             0.050                                                                              0.200                                                                              15.000                                                                             75      13.0                                                                              2.2 × 10.sup.4                                                                8.9                                        17* 98.950                                                                             0.050                                                                              1.000                                                                              0   71      4.5                                                                               6.0 × 10.sup.3                                                                6.0                                        18  98.945                                                                             0.050                                                                              1.000                                                                              0.005                                                                              69      11.0                                                                              1.5 × 10.sup.4                                                                2.9                                        19  98.750                                                                             0.050                                                                              1.000                                                                              0.200                                                                              58      12.5                                                                              2.0 × 10.sup.4                                                                2.4                                        20  97.950                                                                             0.050                                                                              1.000                                                                              1.000                                                                              60      13.2                                                                              2.2 × 10.sup.4                                                                2.8                                        21  88.950                                                                             0.050                                                                              1.000                                                                              10.000                                                                             67      13.7                                                                              2.3 × 10.sup.4                                                                3.7                                        22* 83.950                                                                             0.050                                                                              1.000                                                                              15.000                                                                             101     13.1                                                                              1.7 × 10.sup.4                                                                8.7                                        23* 89.950                                                                             0.050                                                                              10.000                                                                             0   61      4.8                                                                               6.0 × 10.sup.3                                                                7.0                                        24  89.945                                                                             0.050                                                                              10.000                                                                             0.005                                                                              57      10.7                                                                              1.5 × 10.sup.4                                                                3.7                                        25  89.750                                                                             0.050                                                                              10.000                                                                             0.200                                                                              49      11.4                                                                              1.7 × 10.sup.4                                                                2.5                                        26  88.950                                                                             0.050                                                                              10.000                                                                             1.000                                                                              56      11.7                                                                              1.9 × 10.sup.4                                                                3.9                                        27  79.950                                                                             0.050                                                                              10.000                                                                             10.000                                                                             73      10.7                                                                              1.9 × 10.sup.4                                                                4.1                                        28* 74.950                                                                             0.050                                                                              10.000                                                                             15.000                                                                             110     10.5                                                                              2.1 × 10.sup.4                                                                9.5                                        29* 84.950                                                                             0.050                                                                              15.000                                                                             0   79      5.1                                                                               5.0 × 10.sup.3                                                                7.9                                        30* 84.945                                                                             0.050                                                                              15.000                                                                             0.005                                                                              75      9.9                                                                               8.0 × 10.sup.3                                                                7.5                                        31* 84.750                                                                             0.050                                                                              15.000                                                                             0.200                                                                              74      10.4                                                                              8.0 × 10.sup.3                                                                8.3                                        32* 83.950                                                                             0.050                                                                              15.000                                                                             1.000                                                                              80      11.3                                                                              9.0 × 10.sup.3                                                                10.2                                       33* 74.950                                                                             0.050                                                                              15.000                                                                             10.000                                                                             110     10.0                                                                              9.0 × 10.sup.3                                                                11.4                                       34* 69.950                                                                             0.050                                                                              15.000                                                                             15.000                                                                             149     7.2                                                                               7.0 × 10.sup.3                                                                25.8                                       __________________________________________________________________________      *Conparison sample                                                       

EXAMPLE 17

SrTiO₃, very small amount of Nb₂ O₅ which was existing from initial stage of material (contents of Nb₂ O₅ of the material used in the present example was 0.050 mol %), Ta₂ O₅ as oxide of metal for accelerating semicondoctorization and Gd₂ O₃ as an element to improve non-linearity are formed, reduced and fired, and oxidated in the similar operation as that of the above-mentioned EXAMPLE 13. Results obtained by measuring in the similar condition as that of the above-mentioned of the characteristics of devices thus obtained were shown in TABLE 17.

                                      TABLE 17                                     __________________________________________________________________________     Sample                                                                             Composition ratio (mol %)                                                                      Characteristics                                            No. SrTiO.sub.3                                                                        Nb.sub.2 O.sub.5                                                                   Ta.sub.2 O.sub.5                                                                   Gd.sub. 2 O.sub.3                                                                  V.sub.1 mA/mm (V)                                                                      α                                                                           ε                                                                           tan δ (%)                            __________________________________________________________________________     1*  99.945                                                                             0.050                                                                              0   0.005                                                                              105     1.0                                                                               4.0 × 10.sup.3                                                                45.6                                       2*  99.750                                                                             0.050                                                                              0   0.200                                                                              110     1.1                                                                               4.0 × 10.sup.3                                                                40.1                                       3*  98.950                                                                             0.050                                                                              0   1.000                                                                              178     1.2                                                                               5.0 × 10.sup.3                                                                32.3                                       4*  89.950                                                                             0.050                                                                              0   10.000                                                                             218     1.6                                                                               8.0 × 10.sup.3                                                                29.6                                       5*  99.945                                                                             0.050                                                                              0.005                                                                              0   80      3.0                                                                               5.0 × 10.sup.3                                                                8.6                                        6   99.940                                                                             0.050                                                                              0.005                                                                              0.005                                                                              84      6.6                                                                               7.0 × 10.sup.3                                                                4.5                                        7   99.745                                                                             0.050                                                                              0.005                                                                              0.200                                                                              82      9.7                                                                               9.0 × 10.sup.3                                                                3.6                                        8   98.945                                                                             0.050                                                                              0.005                                                                              1.000                                                                              89      10.0                                                                              1.5 × 10.sup.4                                                                2.6                                        9   89.945                                                                             0.050                                                                              0.205                                                                              10.000                                                                             100     12.7                                                                              1.7 × 10.sup.4                                                                3.2                                        10* 84.945                                                                             0.050                                                                              0.205                                                                              15.000                                                                             121     12.9                                                                              1.9 × 10.sup.4                                                                6.9                                        11* 99.750                                                                             0.050                                                                              0.200                                                                              0   75      3.4                                                                               5.0 ×  10.sup.3                                                               5.2                                        12  99.745                                                                             0.050                                                                              0.200                                                                              0.005                                                                              83      7.0                                                                               1.1 × 10.sup.4                                                                3.0                                        13  99.550                                                                             0.050                                                                              0.200                                                                              0.200                                                                              75      9.0                                                                               1.6 × 10.sup.4                                                                2.5                                        14  98.750                                                                             0.050                                                                              0.200                                                                              1.000                                                                              83      10.6                                                                              2.0 × 10.sup.4                                                                2.3                                        15  89.750                                                                             0.050                                                                              1.000                                                                              10.000                                                                             92      11.2                                                                              2.4 × 10.sup.4                                                                2.7                                        16* 84.750                                                                             0.050                                                                              1.000                                                                              15.000                                                                             101     11.9                                                                              2.6 × 10.sup.4                                                                8.4                                        17* 98.950                                                                             0.050                                                                              1.000                                                                              0   71      4.5                                                                               6.0 × 10.sup.3                                                                6.0                                        18  98.945                                                                             0.050                                                                              1.000                                                                              0.005                                                                              89      9.1                                                                               1.3 × 10.sup.4                                                                2.7                                        19  98.750                                                                             0.050                                                                              1.000                                                                              0.200                                                                              65      0.3                                                                               1.4 × 10.sup.4                                                                2.4                                        20  97.950                                                                             0.050                                                                              1.000                                                                              1.000                                                                              70      11.2                                                                              1.8 × 10.sup.4                                                                2.9                                        21  88.950                                                                             0.050                                                                              1.000                                                                              10.000                                                                             76      12.9                                                                              1.9 × 10.sup.4                                                                3.2                                        22* 83.950                                                                             0.050                                                                              1.000                                                                              15.000                                                                             106     12.3                                                                              1.7 × 10.sup.4                                                                9.6                                        23* 89.950                                                                             0.050                                                                              10.000                                                                             0   61      4.8                                                                               6.0 × 10.sup.3                                                                7.0                                        24  89.945                                                                             0.050                                                                              10.000                                                                             0.005                                                                              65      9.5                                                                               1.5 × 10.sup.4                                                                3.5                                        25  89.750                                                                             0.050                                                                              10.000                                                                             0.200                                                                              57      10.1                                                                              1.8 × 10.sup.4                                                                2.3                                        26  88.950                                                                             0.050                                                                              10.000                                                                             1.000                                                                              68      10.9                                                                              2.3 × 10.sup.4                                                                3.4                                        27  79.950                                                                             0.050                                                                              10.000                                                                             10.000                                                                             84      11.8                                                                              2.5 × 10.sup.4                                                                3.7                                        28* 74.950                                                                             0.050                                                                              10.000                                                                             15.000                                                                             121     10.2                                                                              2.0 × 10.sup.4                                                                10.1                                       29* 84.950                                                                             0.050                                                                              15.000                                                                             0   79      5.1                                                                               5 × 10.sup.3                                                                  7.9                                        30* 84.945                                                                             0.050                                                                              15.000                                                                             0.005                                                                              89      8.5                                                                               8.0 × 10.sup.3                                                                6.9                                        31* 84.750                                                                             0.050                                                                              15.000                                                                             0.200                                                                              84      8.1                                                                               9.0 × 10.sup.3                                                                8.3                                        32* 83.950                                                                             0.050                                                                              15.000                                                                             1.000                                                                              90      7.7                                                                               9.0 × 10.sup.3                                                                10.4                                       33* 74.950                                                                             0.050                                                                              15.000                                                                             10.000                                                                             119     7.5                                                                               8.0 × 10.sup.3                                                                16.4                                       34* 69.950                                                                             0.050                                                                              15.000                                                                             15.000                                                                             153     5.6                                                                               6.0 × 10.sup.3                                                                24.9                                       __________________________________________________________________________      *Comparison sample                                                       

As shown by EXAMPLES 13 through 17, in a case Ta₂ O₅ with its added value of 0.005-10.000 mol % and small amount of Nb₂ O₅ contributes to reduce specific resistance of the reduced fired body, and by re-firing in air it shows baristor characteristics.

Herein, the amount of Nb₂ O₅ was that of impurity naturally included in starting material TiO₂, and was in a range of 0.001-0.200 mol % as a result of analysis.

Though for semiconductorization of SrTiO₃, Ta₂ O₅ is more effective than Nb₂ O₅, the effect of Ta₂ O₅ is not damaged even in the case wherein Nb₂ O₅ is contained at the same time. Accordingly, even when Ta₂ O₅ and Nb₂ O₅ are used at the same time as accelerating agent for semicondoctorization, it is possible to produce the baristor characteristics.

However, in the case when Ta₂ O₅ and Nb₂ O₅ only are added, the electric barrier formed at the grain boundaries is low, and the baristor characteristics are relatively small.

Therefore, when such additive as CdO, BaO, La₂ O₃, Y₂ O₃, Gd₂ O₃ or the like is added, the added substance is segregated at the crystal granule boundaries during the reducing firing, and by re-firing in the air these additives contribute to make the crystal grain boundaries in high resistance, and the baristor characteristics become greater.

Besides, since only the crystal grain boundaries only becomes high resistance, capacitance characteristic is presented between crystal grain-crystal grain boundary-crystal grain.

Accordingly, by adding Ta₂ O₅, Nb₂ O₅ and such additive as CdO, BaO, La₂ O₃, Y₂ O₃, or Gd₂ O₃ to SrTiO₃, it is possible to provide characteristics combining the baristor characteristics and the capacitance characteristics. The case such effect is presented is within a range that Ta₂ O₅ is 0.005-10.000 mol %, Nb₂ O₅ is 0.001-0.200 mol %, CdO, BaO, La₂ O₃, Y₂ O₃, or Gd₂ O₃ is 0.005-10.000 mol %.

Though in the above-mentioned EXAMPLES 25-31, the cases where an additive is added in a single one, it was confirmed that even when in place of the above-mentioned, an oxide of Ca, In, Cs, Sn, Sb, W, Pt, Tl, Eu, Tb, Tm, Lu, Th, Ir, Os, Hf and Ru as single one in a range of the above-mentioned predetermined amount was added, the similar effect was obtained.

Besides, it was confirmed that the same effect was obtained even when two kinds or more of oxides of these Ca, Cd, In, Ba, La, Y, Cs, Sn, Sb, W, Pt, Tl, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf and Ru were used in a manner that total added amount is within the above-mentioned range.

When electrodes were provided by conductive material such as Ag or thus obtained element, and a noise filter shown in FIG. 4 was constituted therewith, and noise input A shown in FIG. 5 was impressed thereon, an output of the same characteristics as that of the noise output B was obtained.

As is apparent from this, the noise is sufficiently eliminated, and also by combining the element unit and the coil the number of component is reduced, and miniaturization becomes possible.

POSSIBLE UTILIZATION IN INDUSTRY

As has been elucidated, according to the voltage-dependent non-linear resistance ceramic composition, absorption of surge impressed on the electric and electronic apparatuses and elimination of noise can be done by a single element, and it has many functions and can be miniaturized and is indispensable for protection of semiconductor product of the electric and electronic apparatuses, and practical utility thereof is extremely great. 

We claim:
 1. A voltage-dependent non-linear resistance ceramic composition comprising 80.000-99.990 mol % of SrTiO₃ and 0.005-10.000 mol % of Dy₂ O₃ and 0.005-10.000 mol % in the form of oxides of at least one element selected from the group consisting of Ca, Cd, In, Ba, Cs, Zr, Sn, Ni, Fe, Pt, Tl, Si, Be, Li, Ir, Os, Hf and Ru.
 2. A voltage-dependent non-linear resistance ceramic composition,which comprises 79.800-99.989 mol % of SrTiO₃, 0.005-10.000 mol % of Dy₂ O₃, 0.001-0.200 mol % of Nb₂ O₅ and 0.005-10.000 mol % in the form of oxide(s) of one or more element selected from the group consisting of Ca, Cd, In, Ba, Cs, Zr, Sn, W, Ni, Fe, Pt, Tl, Si, Be, Li, Ir, Os, Hf and Ru. 